Apple doesn't want to license OS X because it would vastly eat into their hardware sales. OS X is not meant to make them money on it's own, it is meant to persuade people into buying Macs. I think that is one of the reasons Apple has mostly looked the other way from the hobbyist OSx86 community. They know that it gets some people to try OS X who wouldn't otherwise. Some will come to love the OS, and decide it's worth going with an Apple box to have, and BOOM, hardware customer. Heck, if they're lucky the OSx86-er even payed for the original Hackintosh license anyhow.
Even if Apple is forced to license the OS out, I don't think they can legally forced to support it on 3rd party hardware, just to not take any actual measures against 3rd party installs. Debateably (I haven't looked into it enough), aside from some lines in the EULA, they already do it this way. If it is licensed, driver support may be pretty sketchy. They may also be able to keep it mostly in house through a loophole (at least for a little while) by saying "We want to continue to only support EFI booting. It isn't our fault other PC vendors choose not to make EFI boards."