[Splines]

I think the only viable way to do this would be for Apple to make Macs obsolete. Like boiling a frog, if they upscaled the ipad to a desktop-lite device over the next few years, and eventually replaced their fully featured cousins with these devices, they would be able to accomplish it with far much less resistance.

(The iMac may have been a few years too early - they could have positioned the iMac as the trojan horse in this story).

[St-Clock]

But you need a Mac to develop most (i)OS applications and I cannot imagine some of the more complex apps being developed on an iPad-like device.

[untog]

It's all about where the mass market is. Just like the low-selling Mac Pro machines, Apple could quite happily keep OS X going for the professional minority that require a POSIX-like experience. The vast majority would use a slightly upgraded iOS, where all of that is hidden away.