All the centralized blog sites go through the same general syndromes. The value of them is that they're a single name to remember in order to get to a lot of varied content. The harm of them is that eventually they start removing people for political reasons ("deplatforming") or doing various other things the content creators don't like, but have little power to stop.

I wouldn't create an alternative to Medium, because I just think it's the wrong approach. We know the answer, because it's what everyone had no choice but to do before: run your own stuff, host it yourself, own your own domain, have your own process, keep things much more under your control. RSS.