The Hackintosh movement is still going strong. One would think Apple would make their life difficult but quite the opposite appears to be the case: there are a few well-understood workarounds to get OS X working on an off-the-shelf PC, mostly just audio and networking. Be careful if you choose not to follow the guides, though! There's a reason most Hackintoshes use Gigabyte motherboards, Atheros wireless, etc. - Just…
To be fair, I also suspect that widespread piracy in the early days of personal computers actually contributed to Microsoft's monopoly by creating a price point that nobody could compete with.