Comment by cwyers

Well, that's not really the whole story, though. Look at Linux. Linux is "open." Linux is also a much harder target to write software for than OS X or Windows, because a lot of people do a lot of different things with that openness, and so you can't count on a specific version of certain APIs or ABIs being there. If modern CPUs looked like modern Linux distributions, a lot more effort would be required to make software portable and to run widely. (The irony here is that ARM resembles this Tower of Babel situation a lot more than x86 does.)