Back when you could still use a mac for things, it came down to the fact that audio and video out of Mac was time-accurate while audio and video out of windows was not. This improved somewhat with ASIO but the fact of the matter is, the timing spec on USB allows audio and video data packets to slip while the timing spec on Firewire does not. Timing wasn't a concern for Windows, but it absolutely was for Mac, from OS 1 clear up through OS 9 and into the OS X adventure.

Windows has caught up but there's still the problem that all the big video editing systems and all the big audio editing systems are written for mac, then ported to windows. I beta test some of the big guys and can confirm that the bugginess and problematic behavior encountered in Windows is an order of magnitude higher than it is on mac, probably for this very reason. Meanwhile, the only video editor of any merit you can run on Linux is Lightworks, which has effectively no audio editing capabilities and zero interoperability with the rest of the world.

It really is hardware-driven. The '00's were entirely driven by Final Cut, an editing program purchased by Apple that was really quite good and utterly unavailable on Windows. Avid, makers of Media Composer (the "big boy" NLE), retaliated by releasing MC and Symphony for Windows but the penetration was never as good as on Mac for all the reasons listed above. Then Apple shit the bed with Final Cut X and everyone went "shit - are we spending the money on MC/Symphony or are we slummin' it in Premiere?"

And Premiere will run on PC, sure, but you've already capitulated by running it. Why the fuck would you capitulate further by introducing Windows into your life?

Fully half my plugins are unavailable on Windows.