Successful open source projects historically involve a bunch of companies lowering their costs by commoditizing expensive commercial functionality. Server operating systems, version control, programming environments used to be very expensive.

Linux, git, Python, Postgres, etc weren’t about getting rich, but about making something cheap and easy.

The paradox of these single company backed OSS projects is somehow making a big chunk of it free/open but collecting money off of other services. To me, I’m not sure that’s worked yet. Many will even say that these companies aren’t really doing open source in the traditional sense, but acting as commercial vendors that let you look at the code.