While it’s important to focus on the backend itself, why don’t anyone focus on the clients which talk to the databases, it is there most of an applications problem starts also in regards to performance.

Lack of protocol compression is painful with postgres

Sure, but that is rarely the biggest issues facing a client: top contenders are always queue, pool and decoding. And obviously lack of SQL being a first class in most languages.

Untrue since the introduction of zstd support in PostgreSQL 15.

Are you sure?