They recently held a small event for a handful of journalists to discuss the Mac Pro and Pro hardware/software in particular. To sum it up, they acknowledge tha

They recently held a small event for a handful of journalists to discuss the Mac Pro and Pro hardware/software in particular. To sum it up, they acknowledge that they made a bet (dual GPUs) which hasn't paid off (software is optimised for larger single GPUs), and which they can't reverse because of the design they went with (they kept referring to a "thermal" corner, but it's a combination of the new cooling system and the boards in the Mac Pro which means a larger single GPU won't fit). They also mentioned something interesting which perhaps contradicts some of your post, which is that many of their Pro customers are moving towards iMac as their machine of choice. Not because the Mac Pro is out of date (it wasn't always), but because that suited them better. I think the implication here is that for most Mac users, and most pro Mac users, a Mac Pro is not necessary.