His story, while informative, is nowhere near close to that of a typical musician or even audio geek. It's not the platform but the software running on it that counts. The first thing Apple did when they bought Emagic and, as a result, Logic Pro was to kill the product on Windows knowing well users would switch to OS X just to use their favourite tool (why wouldn't they given the $1200->$499 price drop and a major feature boost in Logic Studio).
Most musicians nowadays want more than the ability to record and play back audio tracks. What about the digital audio workstation (DAW) choice on Linux; the virtual instruments and FX plugins; MIDI editing and automation; a UI intuitive and simple enough to use at a live show etc. Good software in the creative market seems to take years to build but the user base is so loyal it takes massive effort to get users to switch. There is a reason most software used in the studio is decades old (see Cubase or Logic, for instance: http://en.wikipedia.org/wiki/Logic_Pro#History). There is also a reason why GarageBand had significant time dedicated to it at the iPad keynote. Musicians with computers tend to be geeks to a degree, but at the end of the day they have music to compose and perform, and the less time they have to spend on software and setting it up the better.
Basically, Linux not being embraced among the musicians is the same story of why you don't see very many people jump ship from Adobe Photoshop in favour of GIMP.