The ultra high-end market has always been turbulent. Look at Silicon Graphics. They dominated for a good stretch, but then a wave of less expensive windows base

The ultra high-end market has always been turbulent. Look at Silicon Graphics. They dominated for a good stretch, but then a wave of less expensive windows based machines (like Integraph) followed by commodity graphics-card powered PC boxes completely decimated that market. During that entire time Apple was always positioned in a niche. For a time it was desktop publishing, video editing, photography, audio. A lot of that had to do with loyalty of the developer community, who produced killer apps that only really ran on Apple hardware, as well as appealing to a customer base that deeply preferred Mac OS. But it's worth keeping in mind that the Mac Pro wasn't really ever dominate in certain high-end spaces like 3D. I mean, I'm pretty sure I remember hearing that the ID team at Apple was for a long time using non-apple hardware to run their CAD stuff until one day Ive and Jobs were like, 'this is unacceptable'.