You also can't just join a commercial software project. But you can fork an open source one. For most open source software projects, the "user base" is develop

You also can't just join a commercial software project. But you can fork an open source one. For most open source software projects, the "user base" is developers who like open source software. That's a good thing really; otherwise, there would be nothing that works well for people like me, as all commercial software companies go after the much bigger markets.