[Walter Soyka] "There are plenty of things Apple could have improved in a 2011 Mac Pro besides Sandy Bridge"
You're correct.
If they are going to kill the Mac Pro, why haven't they done so already?
It's been a long time since any significant upgrade.
(My own early 2008 3.2 GHz 8 core, 24 GB RAM, 5770 and Quadro 4000 works pretty good)
Sales of Mac Pros are (without any real data) far below that of the rest of their line.
Not only can you not buy a Mac Pro in their hugely successful stores (and yes, I've bought a Mac Pro in one) but you can't even buy small cheap graphics cards in their stores. (I tried)
FCS has been replaced by FCP X. Leaving user without necessary features to get their job done (which their competitors have) and looking elsewhere for what they didn't replace.
They plan on supporting Video monitoring with FCP X in early 2012, which can be done with Thunderbolt. Already in all but a Mac Pro.
Their fastest iMac runs FCP X as fast as their fastest Mac Pro.
Mac Pro 3.33 GHZ, 24 GB RAM, 5870 GPU
iMac 3.4 GHz, 16 GB RAM, 6970 GPU
http://barefeats.com/fcpx01.html
Reading through all these discussions it appears there are some in this industry that could get by without a Mac Pro and some who cannot. So I think it's fair to say not all users in this industry would leave Apple behind if they dropped a Mac Pro.
Apple's not squeamish about dropping stuff. Dropping stuff without waring. Replacing stuff while leading users to believe the new version will be much better, when it's not.
Apple knows people want a new Mac Pro. Of course they have people read forums where this is debated, especially their own Mac Pro forum. They read it, they just choose not to respond. They read all the rumors and speculation as well. Every company does. People have provided Apple feedback and even emails directly to senior management requesting a new Mac Pro.
They could drop the Mac Pro right now. I don't think anyone would be surprised. I think those who have considered moving away from Macs (for a variety of reasons leading up to this point) have either decided that's what they will do, or they are doing it. As this OP is doing this very weekend.
So, why haven't they killed the Mac Pro?
My guess is (and has been for a while) that they plan on either bringing out a new Mac Pro, or something they feel will be a good enough replacement for one. Most likely they've been waiting on Intel. Now it appears they should be ready.
I see no other reason for them to keep the Mac Pro around, if they have no intention of every upgrading it again. Selling more computers that are planned for end of life means more consumers they'll have to support for a longer period of time.
Then again, I could be wrong.