[ska]

> work on interesting projects, why not start your own?

For what it's worth, many people who don't need the paycheck, or don't need a particular paycheck still go to a "real" job just because the scope of what they can do on their own doesn't match what they want to achieve.

People also join projects to learn things that are harder/less efficient to learn on your own.

I'm certainly not saying you can't do an interesting project on your own, just that many people are interested in projects they can't practically do on their own. Some might scratch that itch with an open source project or whatever, but especially if it requires hardware development, it may not be practical for many individuals.