Spent a long time comparing a "low"-end Mac pro with the highest-end i7 iMac recently, and I came to the conclusion that, for my needs (media production, music composition), a Mac Pro just made no sense at all.

The Mac "pro" market is heavily skewed toward media types, and especially with i7 iMacs there to do much (if not all) of the heavy lifting, I'm not surprised that the Mac Pro is nearing the end of its life.

I'm sure there are a lot of situations that Thunderbolt and i7 don't address, but I'd posit they don't crop up in a vast majority of Apple's "pro" niche.