There are two conflicting theories about the dispersion of the people speaking proto-Indo-European (by which I mean the common ancestor of the Indo-European languages, excluding Hittite and other related Anatolian languages), one seeing it around 5000-6000 Before Present (BP), the other one much earlier, between 7500 and 10000 BP. I know that the first one (5000-6000) had the support of most historical linguists, and I know many of the arguments supporting it (like the fact that there is a reconstructed word in proto-IE for the wheel, and archeology tells us the wheel was not invented much earlier than 5500 BP). The second hypothesis, often linked with the hypothesis of an Anatolian homeland for proto-IE, was revivified in 2003 when Gray and Atkinson published in Nature a paper using computational methods inspired from biology to reconstruct the tree of Indo-European languages, and the date of the dispersion of proto-IE around 7900 BP (and the separation of the pre-proto-IE ancestor of proto-IE and Hittite around 8700 BP).
Now I know that Gray and Atkinson's findings, especially the dating, were not accepted at that time by the majority of linguists. But it was 11 years ago, and I'd like to know:
Have the positions of the community on the date of proto-IE changed since then? Is there a consensus or a quasi-consensus on the question? What is it?
I would also be interested by any pointer to a recent (say from the last five years) article or survey on it. I have found none addressing this question of dating.
I wonder in particular if other people working like Gray and Atkinson with computational methods, but with a different dataset or methodology, have found a date more in line with the traditional view of 5000-6000 BP. Or if, on the contrary, traditional linguists have changed their mind and began to accept a much earlier date (but I would be surprised if this was the case).