@Robbie - Not Automattic per se, but Matt M himself. Consider this from 2010.

http://ma.tt/2010/08/syn-thesis-3-switchers/

While not in that post any more, Matt at the time offered to buy any commercial theme that was GPL licensed to those who wanted to switch away from Thesis.

http://jamesrlee.info/2010/08/switch-thesis-canvas-woothemes/

So if Matt Cutts made the switch on his own, then just about all of these comments have 0 worth and we can go about our merry way again. But the stuff I have linked to shows that in the past, there was at least some effort to get people off of Thesis and to switch to something else. Carl and anyone else concerned with that business practice is saying is that after three years, the practice of talking people into switching themes should be non-existent.

However, I always give Matt Mullenweg and Automattic the benefit of the doubt because history has proven that they deserve it.

I've reached out on Twitter to Matt Cutts to see if he could simply respond here to clarify how the migration process went about.