The problem with fanaticism is it means people will NOT convert from what they're already using. Like I said, Apple already has a *nix distro. It's not exactly converting raging stadiums full of fans. It's free, it has the same features as Linux or Unix, and it has the benefits of backing by one of the biggest IT players on the planet. No, I don't think that you'd get people converting from Linux to OSX just because they made it available on non-Apple hardware. People who use Linux aren't intested in ease of use. That's why they don't use Windows.
I don't think we'll see an immediate shift of most users. Linux users give lots of reasons for using Linux, but when it comes down to it, very few of them even switch distibutions unless it stops being developed. They are as stuck on what they use as any other OS user. If anything, if Mac OS started getting a huge share of commercial OS users I think you'd see a lot more security threats targeting Mac OS instead of just Windows. Which brings people back to using Linux or Unix again.