Well you’re just asking an economic question, are the costs worth the benefits?
I’d argue that linux will never be a good or user friendly operating system without case insensitive filenames.
That isn’t an opinion but could be verified through scientific study of how confused people act. You don’t even need computers, just ask someone to get the “something SomeTHing” from a labeled box in a cupboard. Presumably science would show that case insensitive naming of things is always less confusing when humans actually use the system.
The truth is that programmers enjoy writing code far more than reading code. And especially to open source developers “usability” is a dirty word. It’s not about the value of a thing, it’s about the beauty of how it is done.