To answer the question above...
When computers were coming of age, there were 2 main choices- IBMs, which had a DOS interface, and apples, which had a mouse. Do you think you average artist is going to want to spend time coding and learning to program to make things on the computer? No, so they all went to apple and they have been mainly loyal ever since.
I f**king hate macs, but i'm a designer and I have to use them (everyone else does, cross-formating is a bitch).