I think that we are blowing Mac "fears" of OSX86 piracy completely out of proportion. I have a sneaking suspicion that Steve and his crew would like nothing more than OS-X86 to be available tomorrow running on hundreds of x86 PCs across the globe. Let's face it, for your average person, the OS is moot. Joe Average User wants "tools" to get work done quickly and in time to get home for little league. He could care less what the OS running things looks like.
(NB: We're assuming that consumer OSs are pretty much limited to Windows and OSx here... granted there are other user friendly OS's but they aren't really hitting the mass market....yet.)
If we consider that OS-X has a comparable suite of tools to get work done as your standard consumer friendly MS OS - then the next barrier to entry becomes cost. It's a version of the all things considered equal: most people can't tell you the difference between two HP laptops running versions of windows, so how do you explain to the guy who's trying to buy a new system at the local best buy or circuit city that these two pieces of hardware do pretty-much the same thing, but you're going to pay a 25% premium because that other one *looks* cooler. Joe Average is likely to judge technology in a simple, superficial way; one of the most superficial methods available is price. If the windows pc lets him get email and surf the "inter-web" *and* costs less welp, then that's the choice to make.
What gets interesting is when someone has made this investment and they aren't happy with windows. Currently, they're stuck. Most people don't have a geek friend that will happily burn them a user friendly distro, or spend the next three weeks teaching them how to build a BSD box. The old scenario for someone wishing to switch from windows to OsX would be something like:
Step 1: "Buy new pc that is two or three times the cost of current cheap windows box."
Step 2: "Pray that you really like OSX"
If OS-X is unlocked and allowed to roam free, then people are now free to try out OS-X with a minimal investment in the software. Don't like it? No problem, go back to windows. Shucks, if Apple was really devious, they would be paying people to create live-cd distros of OS-x86 to hand out to people so that you could have as many people trying out their OS as possible. Remember, for your average user, the benefits of an OS designed with usability in mind are too intangible for them to switch. Windows "works well enough". Joe Average User has to see, touch and feel the improvement for it to be real. The only way to get Joe Average to switch is to provide him a low risk environment where he can experience the user-interaction elation that Mac users are always going on about. Mac could have an army of people using their OS on "unsupported" non mac hardware - a great guerrilla tactics way of increasing market share.