> Ethereum nodes/L2s with optimistic or zk-proofs are probably the most advanced distributed databases that actually work.

What are you comparing against? Aren't they slower, less convenient, and less available than, say, DynamoDB or Spanner, both of which have been in full-service, reliable operation since 2012?

I think they mean big-D "Distributed", i.e. in the sense that a DHT is Distributed. Decentralized in both a logical and political sense.

A big DynamoDB/Spanner deployment is great while you can guarantee some benevolent (or just not-malevolent) org around to host the deployment for everyone else. But technologies of this type do not have any answer for the key problem of "ensure the infra survives its own founding/maintaining org being co-opted + enshittified by parties hostile to the central purpose of the network."

Blockchains — and all the overhead and pain that comes with them — are basically what you get when you take the classical small-D distributed database design, and add the components necessary to get that extra property.

Ethereum is so good at being distributed than it's decentralized.

DynamoDB and Spanner are both great, but they're meant to be run by a single admin. It's a considerably simpler problem to solve.

Which are both systems with a fair amount of theory behind them !

the big difference is the trust assumption, anyone can join or leave the network of nodes at any time