Never worked in any of these places. I'm not 100% convinced that they're all equally on-the-ball -- in particular, I've always thought Apple software was an awful dog's breakfast, though their styling is kewl, and Microsoft makes anybody look good. Even Sun. But even so, of course one has to allow the point that some companies do make a better product than others. I daresay it's not monocausal.
An upstart company that succeeds in making a place for itself in an established industry can probably only do so by making a better product than the established players. The organizational equivalent of random genetic mutation no doubt sees to it that companies do come into being that for whatever reason have developed an internal style of work that does make for a better product.
Once companies become established and dominant, though, I suspect that the forces I mentioned before tend to start operating. Maybe the successful, quality-oriented upstart's immune system can resist the executive bacilli for a while, but I doubt that such resistance can continue indefinitely. And moreover, once the infection is well advanced, I bet it's irreversible -- even with a CEO who really does _want_ to reverse it; we shouldn't make the mistake of assuming that CEOs are omnipotent within their their little cosmoi.
Maybe IBM's return from the brink of the grave can be cited as a counter-example to the irreversibility of organizational decay, but I'm not entirely convinced of that -- and IBM is a place where I _have_ worked.