@laurenshof that's interesting. I see your point, but that doesn't feel the same as a truly centralized system - alternative "big accounts" can arise & be used/recommended *without* users needing to migrate to a new system and lose/recreate social links, & no middleman is able to control association.
It's a different kind of centralization where (it seems to me) the vast majority of harm is mitigated.
But you clearly know and think about this much more than I do - maybe I'm missing something?