Conceptually, a potential great thing about Medium is that 'membership' gets access to all content. So I can brows around whatever diversity and quirkiness and interesting backwaters are here, enjoying whatever parts of it I do.

In the Substack model, I have to pay per writer, to read their stuff and their stuff only. That doesn't appeal much to me, as that's not what I'm looking for as a reader.

The problem of course is that the conceptual great thing about Medium is mostly just that - conceptual, Quality is declining, in my experience. Going on about five years of membership, to me Medium seems to be circling the same toilet bowl that other more nefarious platforms you mention are already well down inside. It's systemically inevitable, when like those other platforms, the business is driven by opaque algorithms and executive suite whims. What originally drew me here - the claims of being writer and reader centric - are proven false by how the platform is actually managed.