I'll push back slightly. If users have become accustomed to a particular way of doing things, doing it that way presents the least amount of surprise, so it is at least a somewhat good UX (in terms of least suprise) even if it is a fundamentally bad UX.

But overall I agree. People would benefit greatly if they took the effort to rethink everything from scratch, even if they ends up in the same place much of the time. It's quite easy to do it if you hold the working belief that you are very smart and most things were designed by people less intelligent than yourself.