In terms of the software industry, Postgres actually is kind of that entity. It predates the entire commercial DB (and, er software) industry and is one of the first implementations of a viable relational database server, back into the 70s.

It has a 40ish year continuous history. (Which is also why it has technical/design warts like process-per-connection that we probably wouldn't do in 2026, but that's another story.)

Even with that I remember getting funny looks 20-ish years ago when I would advocate for using it instead of MySQL.

With databases, reputation is everything.