Wrong. Apple will let you upgrade your video card.What a surprise, Apple wants everyone to buy new computers.
So Apple offered to fix your problem, and you refused. Sounds like you are the cause of your own problem.Thankfully I learned my lesson when the Genius Bar refused to send me a replacement for the X1900 in my 2006 Mac Pro - insisting I had to bring the whole machine in so they could replace the card themselves (because, you know, it's a terribly tricky thing to do).
Like hell am I dragging £4k worth of kit into a shopping mall 20 miles away for them to fix a card that they denied was faulty for nearly 4 years.
I've always been a staunch Mac Pro advocate. I'm now a 100% Hackintosh advocate. And I don't have to worry about what video cards my expensive hardware is compatible with.
I don't run Hackintosh so I can put OS X on a cheaper computer. I do it because I get to put it on a computer I trust. The hell with proprietary desktops, and I can run FCP X on my "Mac" today.
Now you are a criminal and using your own refusal from Apple as a lame rationalization. Honestly, you don't sound like a professional.