The pessimist in me thinks that Apple simply had no idea that there was this sort of demand for pro Macs. I've heard again and again stories about power users

The pessimist in me thinks that Apple simply had no idea that there was this sort of demand for pro Macs. I've heard again and again stories about power users that are editing videos (4K these days) or doing other content creation (3D animation, etc) which can really benefit from high-end hardware. I'm thinking it was more an issue they couldn't figure out a high-end, upgradable Mac Pro which kept their beefy profit margins, and didn't become a support nightmare at a price point that was somewhat reasonable (i.e. less than $10K USD).