As I understand it this is supposed to be done in the client libraries rather than in the server. It’s not that it doesn’t reuse query plans, it just doesn’t do it in core.
Makes most sense for server to reuse across all connections regardless of client, big iron db's have been doing this forever, multiple app servers remember. Even beyond that PG is per connection, so even multiple threads/connection per client there is no plan reuse between them.
