OSS is a side hustle for most people that work it. It might turn into a full time paid gig for some but that's usually based on merit or just being in the right place at the right time. Which of course is nice but not something you can plan on having. Additionally a lot of OSS software is created by people that are doing this as part of their job at some company that happens to have some interest in a project or creates new projects.

Either work for one of those. Or just contribute without any expectations about money. That's not for everyone but it kind of is how a lot of OSS gets created. And mostly hiring for such projects is done on merit based on being an active contributor. If you have a community of contributors, that's a great pool to hire from. You already know the people and their capabilities.

I have a few OSS projects on Github. Most of those are just things I'm interested in doing anyway. I don't mind giving that away. I use a lot of OSS as well in my non OSS development so I see this as just contributing back and being a good OSS citizen. My own little way of providing back.

And it's a useful way to make new freelance projects or jobs a bit less Ground Hog day. If you keep on writing the same code over and over again; just put it out there with some OSS license and next time reuse what you've already written. I've done that between a few startups now (where I was CTO so I could just do that at my discretion). Nice to not have to start from zero.

And there are secondary effects if you are active as a consultant or freelancer in the sense that having some projects that people actually use gives you a bit more credibility as a developer, as an expert, as somebody that knows what they are talking about. Minimum it's just a nice portfolio of stuff you can do. Maximum it actually helps generate a bit of business and inbound for your services. People don't pay for OSS software. But they do pay for support, consulting, etc. And you are the world's leading expert on your OSS software.

I dabble on the side (next to my main job as a CTO) doing occasional consulting on Elasticsearch and related technologies. I maintain a Kotlin client for Elasticsearch/Opensearch which is getting some usage and contributions. Mostly that's just something I use myself; so I don't mind spending some time on it.

Most of my customers are not necessarily into Kotlin; so they wouldn't be using my software necessarily. But it helps them understand that I know what I'm doing and talking about. And it gets me a bit of exposure. OSS is not a bad sales tactic to just put yourself out there.