Apple doesnt care about giving Mac consumers any choice with gaming. If they did, we'd have OpenGL 4, a choice of current graphics cards, and more than 3 graphics cards to chose from.
A headless iMac would be ideal, but Apple also has a big problem with that too...
...I think I see a trend here... Apple doesnt believe in choice. Or maybe the word is banned at the Apple campus... or maybe its not in their vocabulary?
Apple believes in what Apple wants to do. SIMPLE AS THAT. Nothing more needed. This goes for anyone. People will either buy or they won't.
However . . . it is then up to consumers to
decide. By the looks of it, Apple is doing pretty well with their current "gaming strategy", which is focused heavily in Mobile.
In tech circles there has been a percentage of users that have always complained about the videocard options, expandability, etc. Yet, despite that, Macs continue to a) set the standard in consumer satisfaction year after year, and b) they continue to outpace the rest of the PC industry in growth year after year.
You *already know* where Apple's main focus is in terms of computing: the iPad and the App Store model, supported by Cloud services. Macs continue to be important, but the real breakout, forward looking markets are all mobile-related, not to the exclusion of Mac notebooks, but rather shifting toward greater inclusion of the Air form factor.
Your complaints are nothing new. They are historic and rather tired. You might think they are perfectly legitimate. Perhaps they are. But Apple has proven that they could bypass them completely and be wicked successful doing it.
So where is Apple's incentive to do what you want?
**By the way, for the 1000000th time, there WILL BE NO headless Mac box you can tinker with. Any chance for that flew out the window years ago, and especially after January 2010.) You've got the Mac Pro or the Mini. Pick one. If that doesn't suit you, you can always go here:
http://www.dell.com/