Agreed, but this is an opt-in. I'll develop muscle memory when I have a UI configured to my tastes rather than rewire my sinews to a forced interface.

This is an "opt-in" if you will - not a direct change.

Is there any compelling reason for them to "stick" with something? Having the choice is a positive good. Unity's lack of options is what drove me away from it.

Terrible for musicians? Comparatively? There has never been a better time to make one's vocation music for the very reasons you have suggested (albeit it is as hard as it has ever been to get "big"). In the olden days many moons ago musicians (often) suffered in poverty until they caught a record deal - now they can develop from their bathroom, garage, (etc) and connect their music to any audience that is willing to listen to their music (or garbage).