The post quality has deteriorated, and it feels like I'm reading the same posts over and over again. Not to mention the stupid paywall which is infuriating.

Why did Medium end up like this? In the beginning it was pretty good but then it started to wither. Is there any way for a platform like Medium to keep up with high quality posts while also paying their writers well?

Substack has done a good job at competing in the blogging market but it's different from Medium. Medium is more of a social blogging platform while Substack is more of a newsletter platform. Substack doesn't have an algorithm that recommends you content, but instead shows you exactly who you follow. This is nice, but I can't deny that I also like finding new content through a recommendation engine, which Medium also sucks at.