Why would a decentralized Facebook have the same engagement-optimized feed? That’s an artifact of wanting to keep users around as long as possible so as to put ad after ad after ad in front of their eyeballs.

That's like argueing that dictatorship might be better than democracy because at least there is someone to hold accountable.

Well, there is someone who is responsible, but the problem is that you cannot hold them accountable. Which is why democracy avoids the same concentration of power in the first place.

Which is also the whole point of decentralization. You avoid the concentration of power that would allow any single party or small minority to turn against you without any way out for you.

If you email provider starts selling your emails to the highest bidder, you don't need to regulate your email provider. You simply switch to a different one. Or run your own server. Decentralization is about keeping the power your hands.

I would say my comparison is more akin to dictatorship vs anarchy. Obviously neither choice is ideal, so the specifics of how these systems are implemented is vital.

I'm a big fan of decentralization in general, but I think it's worth pointing out where things could go wrong at scale.