Username + Password with a cookie store is much better understood and harder to get wrong than implementing a full OIDC suite (server + client). If you're talking federated login, that's what OIDC is for. If you're talking "login", your opinion is misguided.

We might not be talking about the same thing. The thread was comparing to other OAuth servers, and then libraries, but nobody is talking about implementing it from scratch.

That being said, if you're working on a greenfield app where you need auth, using an OAuth/OIDC server is much better and faster than creating yet another membership system for that app. That's a major advantage of identity federation.