You haven't really looked into postgrest, it does not force the database schema on to the client. You expose a schema with views that are tailored for the frontend and can be totally different from the underlying tables that hold the actual data
Still there are a tone of applications for which just the basic types are good enough and the server is just a thin wrapper.
In the end the main requirement for efficiency using it is you skill with not basic SQL/plpgSQL (stored procedure, trigger functions, views and knowledge about the effects of the used isolation level). All well documented in postgres.
Another way I've heard this phrased is "It's much easier to hire JS devs than PL/pgSQL devs."
Worse is better. Cheap JS devs to solve everything with heaps of imperative code is cheaper than elegant solutions.
Even long term this is true. Tech debt with code that people can understand and modify is cheaper than tech debt with an elegant DSL that require learning and mental ability beyond if then else.
I've recently seen an uptick in "Postgres-native" stuff being built, though. So maybe there's hope for the future.