I understand the sentiment here, but I don't think it's true. There was a recent quote from El Jobso (can't find off hand, sorry) saying that Apple actually sat on the top end of the market with the Mac (in his absence), got greedy, failed to innovate, and suffered.

Instead, look at what they did with the iPod. They didn't just remain as a high-end mp3 player, they developed products which covered nearly the spectrum of the marketplace, while still remaining the high-end brand.

I think past will be prologue, but it should be the iPod, not the Mac, that will be the best example. That said, when you're taking 50% of the profit in the market with just a 4% share, there's not a lot of reason to be particularly unhappy with your current position!