If hackers can do it, certainly ms can
Apple *tries* to restrict installation of OSX to Apple produced and sold hardware. Indeed, it is difficult to install OSX on non-Apple hardware and doing so is in violation of Apple's EULA (or so I belivieve). The OS looks for a unique hardware ID on the MB when it's being installed - if it doesn't find it, it won't run without a lot of hacking. This is 100% on Apple and has nothing to do with MS or with the PC manufacturer. This is a marketing decision on Apple's part - "PC" (or rather, non-Apple PC) manufacturers could care less if you install OSX on their machines but
Apple won't allow it - which I have always thought to be shortsighted because there ARE enough people out there who are fed up with Windows that they might make the switch if they could do it with their existing hardware and Apple could thus grab more of the OS market share. Microsoft, no doubt, is pretty happy about this arrangement BUT they have nothing to do with it and will have no control over it if, in future, Apple releases OSX to the unwashed masses. I suspect that Apple/Jobs know that if OSX were released for use on non-Apple controlled boxes, they'd have a LOT of problems with it fast and the lustre would come off OSX faster than you can say Windows 7 (or XP or Vista)!
No one will dispute your argument that to both companies it's about the money. However, if you continue to brand Microsoft as the "bad guy" in the "OSX won't run on a Microsoft machine (sic)" scenario, you're going to continue to draw rebuttals.
Now, as wraith notes above, when it comes to choosing an Apple versus a non-Apple machine (and thus OSX versus Windows versus something else): whatever floats your boat!