It's very clear that Apple has tremendous foresight, sometimes to their own detriment, with the design of both hardware and software.
Back in the good old days, when I was but a wee little Wirehead, Apple managed to make hardware that was much more compatible and easy to deal with than your average off-the-shelf piece of consumer hardware. You could plug your mouse into your keyboard and the keyboard into your computer. You could add cards and they'd just plain work. You didn't need to write a separate "Program Manager" and "File Manager" because the whole system was conceptually simple enough to make do with just a directory browser.
Apple tried to license their OS in the past, but it almost killed them.
In the past few years, we've finally reached a parity point where plain old Intel hardware is pretty much "good enough" and you can now run a PC operating system on the Mac.
Which really brings up the question of why Apple is preventing you from installing OS X on your computer at home. The argument is made that Apple is able to restrict the available hardware for the Mac so that they don't have driver hell, which I don't quite buy. The existing Mac hardware is all usable in a PC architecture system, easy to find, and able to be used as a "Oh, well if it doesn't have the OS X logo, I guess I can't use it in my PC-Mac" standard.
The way I see things, Apple will not let you run OS X on your PC until the reasons why licensing MacOS didn't work last time don't hold anymore. And we're not there yet.
The first barrier is Office. Apple needs to make sure that they are in a position of power with Microsoft to ensure that Office continues to be available. Alternatively, OpenOffice or an AJAX online office package need to become the standard. This seems awfully close, especially given Apple's mindshare.
The second barrier is the hardware OS-subsidy. See, a Mac gives Apple the opportunity to collect what would be two streams of income. Even without a price premium just for the Apple brand, if Apple were to let HP make computers and charge about what Windows costs for OS X, they'd make less money, assuming they didn't grow their market.
The third barrier is the expense of keeping up. Apple needs a certain amount of effort to be able to keep developing OS X and, at the same time, give it features that are cooler and more interesting than Windows. Right now, they are winning. But if they make less money per OS X desktop, they might fall below the essential income point.
On the other side of the fence, there's the currently untapped market. I'm part of the way in that. See, just about everything I want to do can be done on the Mac. But I've got a PC that I've been incrementally upgrading, so if I wanted to go Mac, I'd have to junk the whole thing. If I could Mac-ify it without doing that, I'd be much more likely to make the jump.
So, what it ends up being is that Apple isn't going to jump until, by their calculations, the income from the currently-untapped market outweighs the potential downside. Corollary: if they get Microsoft-sized, it will likely be anti-trust related.
Oh, and there's one more thing. The MacBook and MacPro are chipping away at the currently-untapped market. See, I've recognized that the MacBook is head and shoulders above any available PC laptop, so any future laptops for personal use are likely to be Apple branded as well. If I stop using my desktop computer as my primary workstation, I'm likely to instead use it as a hefty Linux personal server. The same goes for the MacPro -- because of Intel's Xeon branding, it's easier to get a MacPro as a powerful desktop when one processor isn't enough.