I think financially for Apple they won't give up the hardware business. I don't know the hard numbers, but I would speculate they make the bulk of their money selling hardware and iPods. I think, in theory, that the hardware subsidizes OS X development.
To that end, OSX may only support Apple specific hardware configurations. This has a couple of benefits, not least of which would be a smaller size operating system. (compared to Windows, which has a voluminous amount of legacy hardware to support.)
My $.02, though I'm not super tech minded and may be way off base. Counting down to 1:00PM EST . . .