Open source is a niche. The vast majority of developers don’t participate in open source. If they do, it’s simple bug fixes that they need for their paid jobs. The number of people creating and releasing significant open source projects is vanishingly small relative to the entire pool of developers.
I think it was a mistake to tell entry-level devs everywhere that open source was some sort of secret cheat code to boost one’s career. On the hiring and recruiting side of things, seeing open source contributions is helpful, but it’s almost never the deciding factor in hiring someone. Meanwhile, Internet forums for juniors are full of anxiety about creating side projects and GitHub profiles because young developers think it will get them to the head of the hiring line. It’s a recipe for a lot of disappointment in open source.