That's the harsh reality, first (anecdotally / personal view) it became social media that linked to blog posts - especially Twitter was used as an aggregator for "I wrote a blog post about xyz".

Then Medium took off, and there was a vibe of blog posts being more authoritative if they were published on Medium. It was like the TED talks of blog posts. But also it mean that if you had a blog of your own and its contents were reposted on Medium, the latter would get more views.

I don't have the full picture of the whole issue. I suspect consumers generally want a single website to read stuff on, instead of the sometimes jarring style differences between blog sites - even if that means they have individual personality.