all pretty weak questions.
Take a look at this thread and other threads on this "Mac Pro" forum.
Look at how many people are willing to buy an HP or Dell workstation.
Indeed. Go back to 2008, 2009, and especially the 3 month gap between March and July 2010 and see how many folks were positioning HP/Dell workstations. "Oh , the Mac Pro is horrible because it only has 4 slots" (seem a repeat of that very recently). " 4 PCI-e slots are too few " , " I only need a T3600 or z200-z400 small scale tower " , blah , blah , blah.
There are always folks complaining.
I really think Apple missed the boat on this one.
The certainly missed the boat in getting something timely out. However, it certainly isn't as bad as the JP Morgan trading desk that nuked $4+ billion dollars of that banks money.
How many of these same people would buy an HP or Dell workstation if Apple had launched a Sandy Bridge Mac Pro on June 11th?
The segment of people who dual boot through Boot Camp more than 20-30% of the time are always at a threat of jumping ship. As pointed out above there is a almost constant grumbling from those folks over time. That groaning isn't particularly indicative of anything specifically related to the current context.
There is also a very large segment of the Mac Pro population that isn't going to buy anything. Folks who bought Mac Pro's in 2011 , 2010, 2009, and most of 2008 aren't going anywhere. Because of their high capital costs, Mac Pros have a relatively slow turn over rate.
Again look in through the forum. How many threads are there of folks wailing they can't install Mountain Lion on their 1,1 and 2,1 Mac Pro? Several. There is almost constant thread of complaints they folks can't run their "perfectly good" 5,6,7,8 and 9 year old Mac Pro class boxes and that Apple is "evil" for not supporting their productive, but vintage , hardware. Guess what ? ... they aren't buying anything: HP, Dell, or Apple.
In addition to those, look at the number of threads about how "Lion"/"Mountain Lion"/Windows 8 are evil and that they are sticking with Snow Leopard for as long as possible. Guess what? these 2012 Mac Pros run SL. If Apple rolled out a bleeding edge board with E5's it wouldn't. Mac Pros increments moving at a much slower pace than the OS increments means a machine that can span more OS versions.
So ....
Primarily the people at risk are those who needed to make a "retirement" transition in the next 7-12 months or ran into "top end performance" issues. It is a sizable number but it isn't the whole Mac Pro market.
Sure there is a chunk that have been defering and will bolt, but they relatively small since Mac Pro upgrade cycles are so long. There is always a relative small number of folks on transition points.
How many people are willing to wait for a "really great" Mac Pro in late 2013?
Of those not scheduled to buy until 2013 and beyond anyway? The vast majority.
Will Apple just discontinue the Mac Pro because they will already have lost too many Mac Pro customers?
Again a fundamentally flawed question. It is really about growth. As long as Apple is OK with completely ignoring Mac Pro growth (or lack of growth) over the 2010-2013 time period it really doesn't matter. When Apple has a competitive product if buyers don't buy then they will probably kill it. If Mac Pro growth jumps as high as iMac/laptop growth and holds steady for 4-8 quarters they will probably continue.
I think Apple knows they don't really know enough if it is a viable product or not. There are likely folks internally trying to kill it. But it has probably been given one last shot to "live or die" on the next update. What happens is really up to what the customers do with the next model.
With $100B in the bank and more money then they can spend coming in Apple does not vitality need Mac Pro revenue. However, they won't blow off Mac Pro growth if it existed at rates similar to the rest of the Mac line up. In the meantime I don't think Apple is going to be rattled by FUD that HP , Dell, etc are going to sling for the next year. Uncharacteristically, they'll ahead said a revision is coming next year. They have enough resources to "rebuild" the Mac Pro market incrementally over a 3-4 year period of time if they want without breaking a sweat.
In contrast HP, Dell , etc desperately need relatively very high workstation revenues and profits to cover up their "loss leader" boxes which saddle their overall businesses with about 20-25% less profit margin that the Mac business. The are primarily just trying to get from quarter to quarter. That's largely because Apple doesn't have any loss leader boxes bleeding profits. Apple is quite happy to have just 5-8% of the market.