Apple famously did many years of intense user testing to develop their HIG (and maybe still do?). I’m pretty sure xerox did too, and all the other UI researchers many years ago. Maybe even Microsoft did :)
In any case, it contradicts your claim, since all this user research was way, way before UX was a thing.
Honestly I just got the feeling that the phrase UI had become stale and UX was just seen as a way for a new generation to put their mark on the world.
The 1985 edition "includes e.g. case studies (useful!), and an extended discussion of Jung's theories of intuition and how they should influence your designs (!!)"
In any case, it contradicts your claim, since all this user research was way, way before UX was a thing.
Honestly I just got the feeling that the phrase UI had become stale and UX was just seen as a way for a new generation to put their mark on the world.
Nothing wrong with that, of course.