That's not entirely fair; Apple's comeback has been almost miraculous. I wouldn't bet on most companies making that kind of recovery.
I don't think Apple's comeback (the OS-X based one) was miraculous. They took a basic Unix that the Plan 9 guys would have turned their noses up at, and put a reasonable user interface on it and worked their way through all the tedious parts of making a stable, useful operating system; and then, it did exactly what the linux zealots had been saying was possible with Linux -- it became very popular, and known for being more stable, easier to use, and more secure than Windows.
The miracle is that Windows survived. Given that Apple had a focus on hardware lock-in and the high end of the market, that left Windows a big hole to live in; Linux should have copied OS-X "look and feel" down to every detail, made it run even faster on cheaper hardware, and given Windows a run for it's money.
As one of those linux zealots, I intend this to be self-criticism.
Ubuntu is going to eventually do that, I think. It is not OS-X compairable yet, but it is improving.
Heh. Predictions of the future are always amusing... especially when you live in that predicted future :)
(I hear nobody is using that old "Linux" thing these days. And Macs; they're totally dead.)