Their "reasoning" behind axing the Xserve is perfectly valid for the mac pro. So I wouldn't be surprised.
It would be surprising. At least to do it within 2 years of the XServe being removed.
The reasoning was a combination of relatively low volume and low growth versus the other Mac models. Second contributing category is that don't have a "new" Mac Model to add to line up. ( MBA expanding to 11" and 13" is spreading fixed Mac engineering thinner.)
The Mac Pro was/is not as bad shape as the XServe:
1. Prior to MBA remodel the Mac Pro was selling at a faster clip then MBAs on Apple's online store. Granted Apple has "fixed" the MBA in terms of growth and units with the addition of a lower priced option. They "fixed" the XServe volume to .... with Mac Mini Server.
2. There is no widespread industry trend of virtualizing higher end workstations. A decent number of folks who howled at XServe discontinuation said effectively "Didn't really want your hardware anyway Apple.... if it runs on VMWare on commodity boxes that's all I want". (i.e., "Apple we don't want your software/hardware integration").
Sure there are the "I want a cheaper, more limited mini-tower" folks, but so far there not a ground swell of folks saying don't want to buy workstations anymore. That will probably get a bit louder when the new Xeon E3-1200 series workstations start rolling out. I think a remodeled Mac Pro could show that it has more I/O throughput then what those boxes are going to show.
(e.g, more unswitched PCI-e lanes, more I/O, more cache( less integrated graphics) , etc. )
Additionally, the Mac Pro should get a slight bump in growth from use as Mac OS X Server after the XServe retirement. Apple is likely to wait to see if that is sustainable before canceling the Mac Pro. Merging a subset of the XServe's tech into newer versions of Mac Pro ( boot SSD , front removable drives , LOM option, etc. ) is doable. It doesn't have to become a perfect plug-in replacement for a XServe to sop up a decent fraction of the former XServe market. Just like the top end iMacs didn't need to take on all the characteristics of the Mac Pro to peel off some of MPro market.
However yes, if a growth bump doesn't appear and folks flock to Windows 7, sub $1800 'workstations' then yeah the Mac Pro is in trouble.
Both are bad moves, but apple is trying to think like an economist about the mac line, not like a business strategist.
It is not particularly good biz strategy to keep pursuing something that has no growth and is a shrinking share of your portfolio. They only had to look at a pie chart of the Mac sales to see the XServe shrink into a tiny sliver of the graph. And unlike most of the PC vendors Apple doesn't sell the rest of the PC line up and razor thin margins. So there is no necessity for "Servers" with bulky margins to balance out the low margins.