[randywaterhouse]

I believe, personally, and know others who commit to open-source projects on a personal basis (and then those who I only read of on the internet), that many developers who work on these projects don't need monetary compensation in the normal sense.

Working on an OSS project is fulfilling in ways other than money, and some people really enjoy doing it in their spare time, etc. I know some of my friends from college who went off to do work at Facebook, Google, IBM, and they actually all enjoy submitting their code to open source projects for 0 dollars.

So while you're right there is some sort of "idealism" required, it's a common ideal in the culture of programming it seems. Supporting what one thinks is right, simply by nature of believing in it. Then you can go off to your day job at Google and make six figures.