This is basically my point and what I think is wrong with your argument
Midcore content may be a nebulous term that few people agree on the exact difficulty of but everyone can point to the largest deficit in current difficulty, which is the “harder than juneo easier than extremes” range for people who want content that isn’t a pushover but also doesn’t need PF. It’s functionally irrelevant to the argument that you consider that normal content, it still is a deficit in difficulty that the devs don’t seem to want to touch which is a problem people have.
This doesn’t have to be a unique mode or be a stepping stone to extremes, it just has to be content people want to do and offer some measure of rewards