Apple isn't just a PC maker, their priority it seems, first and foremost is with iOS.
I don't know about how bigger a priority iOS stuff is above the Mac, but whatever that is, Apple still manages to produce marvels of technology like the current MacBook Air's that no other PC-maker is able to replicate. And the real innovations that Lion is bringing about (things like resume/autosave/versions) are really setting the tone of modern computing, much more than animated tiles and typography. So, priority or not, Apple is pretty damn serious about the Mac platform, make no mistake about that.
The overall PC market is bigger and more profitable than iOS devices.
Bigger? Maybe, maybe not. iOS devices compete in the mobile computing market which is already huge and growing at tremendous pace. The PC market is stagnant at best, and probably will shrink sooner than later. (And by the way, the whole point of WP7 and Windows 8 as it is developed is about Microsoft catching up in that area where they're being beleaguered.)
Profitable? Yeah, so profitable that the #1 PC-maker HP is in the process spinning-off its PC division to clean up their bottom-line.