A debate over the PIE homeland

In 1668, Andreas Jager of Wittenberg proposed that there was an ancient language spoken in the Caucasus mountains which then spread throughout Europe and Asia through waves of migration. Mr. Jager did not know about Sanskrit or the similarities between Sanskrit and European languages when he wrote that. A century later,  Sir William Jones discovered that similarity, thus creating the field of historical linguistics. The mother language was postulated to be proto-Indo-European and now there are differing theories on the location of that homeland. One of those theories claims that proto-Indo-European speakers were chariot driving pastoralists from above the Black Sea, who left their homeland around 4000 years back. Another theory claims that, they were from the land below the Black Sea (Anatolia) and were farmers. Along with the spread of agriculture from 9000 years back, the language also spread.
Recently a paper claimed that they had solved the homeland mystery forever.

We used Bayesian phylogeographic approaches, together with basic vocabulary data from 103 ancient and contemporary Indo-European languages, to explicitly model the expansion of the family and test these hypotheses. We found decisive support for an Anatolian origin over a steppe origin. Both the inferred timing and root location of the Indo-European language trees fit with an agricultural expansion from Anatolia beginning 8000 to 9500 years ago. These results highlight the critical role that phylogeographic inference can play in resolving debates about human prehistory.[Mapping the Origins and Expansion of the Indo-European Language Family]

Based on this paper, The New York Times had a graphic which showed the timeline for the evolution of each language tree. If you note the time for Vedic Sanskrit, it falls to around 4000 BCE, which is much earlier than the Mature Harappan Period. This violates many sacred academic lakshmana rekhas. But if you note the time frame for Romani, it is around 1500 BCE, which actually does not agree with the known history of the Romani people, who left North India much later.
Here is a video (via GeoCurrents) where a two Stanford historical linguists   syntactician and historical geographer take the authors of the paper, who are computational linguists, among whom one is a computational linguist, to task calling them “creationists” but thinks this does not rise to the level of Creationism.
[youtube http://www.youtube.com/watch?v=4jHsy4xeuoQ?rel=0]
Another point they make is that PIE cannot be older than 3500 BCE because that was the time the wheel was invented and PIE contains words for the wheel.  Obviously the language cannot contain words for things which did not exist. Now if PIE cannot be older than 3500 BCE, then Vedic Sanskrit cannot be older than that. This is an important point for dating the presence of Vedic speakers in India based on historical linguistics (and not computational linguistics)

  1. Bouckaert, Remco, Philippe Lemey, Michael Dunn, Simon J. Greenhill, Alexander V. Alekseyenko, Alexei J. Drummond, Russell D. Gray, Marc A. Suchard, and Quentin D. Atkinson. “Mapping the Origins and Expansion of the Indo-European Language Family.” Science 337, no. 6097 (August 24, 2012): 957–960. doi:10.1126/science.1219669.
  2. Bryant, Edwin. The Quest for the Origins of Vedic Culture: The Indo-Aryan Migration Debate. Oxford University Press, USA, 2004.