Given that there are language associations that work to standardize languages’ orthography, vocabulary, grammar, etc., why is it not more common to use phonetically accurate spelling?
Because most of the benefits of such a change would be to learners, while most of the costs would fall on the existing users of the orthography.
Where there is no established writing culture (or system) there are in effect no existing users, so it makes sense to make the system easy for learners.
But where there is an established writing culture, there is little incentive to rate the needs of learners above those of existing users, for whom (generally speaking) the system is adequate for their needs, irrespective of how bizarre and awkward it may appear to outsiders.
wʌn ˈɹʷijzn̩ iz ðæɾ ɪndʌˈvɪdʒl̩z ˈdɪfɹ̩ʷ səp̚ˈstæ̃ʃəli ɪ̃ ðɛɹ prʷəˈnʌnsiɛiʃn̩ ʌ wɹ̩ʷdz. In fact, it is extremely difficult to get undergraduate students in a linguistic class to produce an accurate phonetic record of their own speech – it takes a very long time and it is typically very inaccurate. Phonetic writing is completely impractical, as a general practice, though it is entertaining for academicians. Articles in the Journal of the IPA are no longer written in IPA, for good reason.
The problem of variation can be eliminated is we all agree to transcribe according to how the King of England pronounces words, but I could not say how the present monarch pronounces the word "metallurgy", so I would not know how to spell it. Substituting the President of the US gives me a more-accessible model, but also a less permanent model, one that gets rotated out every few years. We could then agree that there shall be two authoritative pronunciations, one for the US and one for the UK (good luck, Canada and India) as represented by The Dictionary. In the US, Congress would decide which dictionary is the official dictionary empowered to set spellings.
The main problem with that plan is enforcement. For hundreds of years, pedants have been trying to correct people's pronunciations, but they have failed. There have recently been changes in pronunciation that tend to reduce regional variation, which are somewhat accidental and not the product of enforcement actions: it is the product of media promulgating a more uniform model.
We can now see the beginning of such a movement in spelling. Simpler more rule-governed (less arbitrary) alternative spellings like nite, rite, flite, site, tite are on the rise. It is commonplace that people will write "I would of told you", befitting the facts of pronunciation.
So much for English. As for Logoori, to take one example, their spelling system was devised about 110 years ago, based on the dialect spoken in one area (where the mission was), and the inventors didn't have any training in linguistics, so they just made it up as they went along. There is no central spelling authority, there is as much variation in that small language as there is in English, and there is an extremely strong tradition of adhering to "proper spelling" as defined in whatever Bible translation you have at hand. Introducing special letters is always a bad idea unless it is packaged well (e.g. the success of the "official" spelling of dxʷləšucid). Somali and Shona spellings are examples of reformed systems that eliminate special letters, and these are generally successful, because these languages simply ignore distinctions that can't be represented with plain Latin letters, and so far, this hasn't proven to be a practical impediment to comprehension (e.g. the lack of tone marks in Shona is not highly significant except when one deliberately constructs texts that are tonally ambiguous). In a few more generations, there will be similar complaints in Zimbabwe about arbitrarily spelling one word with zh but another with zv.
Designing an orthography is a difficult task, and having a phonemic orthography is only one of several goals in this task. Other goals may may include recognisability of morphemes (this is why, e.g., in German orthography Auslautverhärtung is not represented), resolving homophones by differentiated orthography (school kids hate this part of established orthographies most), keeping older books and written records legible (the tradition aspect already mentioned in the comments), keeping the orthography in line with relevant peer languages (Europeans usually find the sound of Pinyin ⟨q⟩ very weird), or keeping some national character.
So, usually phonetically more accurate spellings can be found in younger orthographies, and older orthographies tend to accumulate irregularities.
Also, some speech communities have a tradition of keeping the orthography aligned with contemporary pronunciation (e.g., the speakers of Dutch) while others stick to traditional spelling (notably the speakers of English and French).
One reason is that language is fluid. Pronunciation varies by geographic region, and over time. Which point in both space and time do you use as your standard? What do you do when pronunciation is inevitably different somewhere or somewhen else? Does each region get its own spelling? Should the spelling be updated every decade to reflect the new pronunciations? How do you read old books where the pronunciation has changed or anything written in a region with different pronunciation?
Spelling is a compromise between phonetics, ease of use, and long term comprehensibility. Above all, it must be useful. Different language communities have different priorities of phonetics, ease of use, and comprehensibility. In English, we can read some really old books because although pronunciation has changed so much over the centuries that we would have extreme difficulty understanding spoken English of the time, written English has changed relatively little and is still for the most part comprehensible with relative ease. In Sinhala, each letter has a single pronunciation (or a very small set of allomorphs which map back to that letter, e.g. /w/ and /v/ for the same letter). Reading is very easy. Writing is almost as easy. A few sounds have merged, resulting in some different spellings in modern Sinhala sounding identical (two letters for /n/, two letters for /l/, etc.). This will serve Sinhala speakers well until contemporary pronunciation drifts too far from their orthography. Then they will either have to change their spelling (making existing texts harder to read) or accept pronunciation and orthography having significant differences (like in English), making it harder to read and write, but it being equally easy/hard to read both modern and older texts.
One practical issue is the question of whose English dialect and accent should we standardize to? I pronounce certain words differently than my parents, much less people in other parts of the US, much less people in other countries. A small example is the "cot caught" merger, I pronounce those the same way but my dad pronounces them differently (the merger is happening both by generation and region), so when we reform the spelling do we spell those the same or not?
No matter which dialect and accent you pick words won't be spelled phonetically for most other English speakers. If every person spelled things phonetically based on the way they personally pronounce them it would be extremely difficult to read for other people, so I doubt anyone would want that.
Even if we did implement a spelling reform it would become immediately outdated as language and pronunciation continue to shift.
Spelling reform sounds great until you get into the nitty gritty of how to actually implement it, then it immediately becomes a logistical nightmare.
Pure phonetic spelling sounds like a very good idea, until you actually try putting it into practice.
Take for example Albania. This country has two main dialects: Gheg and Tosk. These dialects do differ quite a bit. When they standardized their written language, they based the new standard language on Tosk. So for Tosk speakers, Standard Albanian is mostly phonetic, but for Gheg speakers that isn't true at all.
The next issue is that spoken language changes over time, while it's good if the written language stays the same (or at least similar) for longer times.
Spoken language changing isn't much of an issue, since it is rather fleeting. I mean, yes, there are voice recordings/movies that do preserve spoken language for longer, but it's (at least not yet) common to look up really old spoken word for any regular use. But in written language that's quite common. Shakespeare, the King James Bible and lots of other old, written works are still in common use today.
They are still quite legible today, even though the spoken language and its pronunciation has changed a lot since then. You can read Shakespeare, but you probably wouldn't understand him talking.
A large rework of the written language (or maybe multiple even reworks) would break this compatibility.
For example, try to read texts from before the written language was standardized. It's not easy at all.
Because it's not worth the struggle against the opposition. So-called "proper spelling" is required to get a job and go through school. Even posting a comment online without accepted spelling will result in being berated with ridicule and low-key threats. The moment anyone tries to spell things phonetically in the workplace will get them fired and shunned from professional communities. Furthermore, there are bound to be disagreements on how to handle silent letters, and even then new letters will have to be added to the alphabet in order to spell otherwise impossible words. Thus people can't simply just start typing phonetically when they choose, new rules must be agreed upon, taught, and learned. This makes adoption hundreds of times harder since it's essentially a whole new language.
While I otherwise agree with the other answers, I'm skeptical as to how much inconsistent pronunciation would actually be a problem. While it's true that the pronunciation of words will likely change over time, this is a very slow process, and I don't think it would be a problem if the written language were to be changed slowly as well. Furthermore, I highly doubt learning multiple spellings for words will be difficult considering humans are capable of learning multiple meanings per word, and memorizing how to spell different words. Not to mention how many books actually do change the spelling of many words to indicate a thick accent, and readers are able to understand them without issue. I think the idea that words have to have the same spelling across accents is just part of the flawed rules of English (among other languages).