Mac OSX is based around Unix. Nuff said
Linux is having a hard time because it IS so open... without proprietary OS's, where is the incentive for the developers to advance it uniformly (which is what app developers need)?
The thing for me is, music, audio and video apps put basically the MOST stress on your computer and OS. Multiple threads running in realtime, VSTi's sucking the life out of your CPU, video and audio/sample streaming to test your data busses to the limits. And now you want to add an 'open' OS to that mix..?
Only the most advanced app developers can get this stuff to work, and now you want them to adapt their apps to an OS that is in a constant state of flux? On hardware in a constant state of flux..? It's no wonder that Mac systems dominate in the PRO world. Stability and reliability (of both OS and hardware) are de rigeur when your entire business depend on them.
Enterprise grade corporate systems don't rely on Windows. And neither should you, IF your living relies on it... IF it's a hobby, no worries. You can AFFORD the downtime while Windows sorts itself out (if it ever can
). Make a living doing video and music production, you had better run something a bit more stable, even at the cost of not being so bleeding edge. There's a REASON they call it the 'bleeding edge'