The fact that Apple is working on virtualisation shows that there is a user demand for running alternative OSes on a Mac desktop. And yet, instead of opening up their hardware just a bit (by making available some hardware literature on their ARM SoC) to system developers, they'd rather offer a more convoluted way of running other OSes only on their terms and control. It's all about having control over your personal d…
I think the better argument is that it is what Apple says it's about, security. For the same reasons, we don't see Windows source code, nor are internally discovered Linux kernel security bugs advertised until they're fixed.
I personally consider security bugs to be just "normal bugs". I don't cover them up, but I also don't have any reason what-so-ever to think it's a good idea to track them and announce them as something special...one reason I refuse to bother with the whole security circus is that I think it glorifies—and thus encourages—the wrong behavior. It makes "heroes" out of security people, as if the people who don't just fix normal bugs aren't as important. In fact, all the boring normal bugs are way more important, just because there's[sic] a lot more of them. I don't think some spectacular security hole should be glorified or cared about as being any more "special" than a random spectacular crash due to bad locking. -Linus Torvalds, 2008
Instead of rolling over and vulnerably showing soft underbelly, armadillos fold in half, tuck in their legs and head, curling their tail beside the head and pull in tight, so that only their leathery armor shell is exposed. If they did what you wanted them to do, their species wouldn't exist for very long.