It's such a common argument at this point that I would disagree that it's a "citation needed".
I wrote an open-source library for a popular service in a popular programming language. I wrote a couple of e-mails and suddenly my library became popular.
Today it has had about 50 different people work on everything from off-by-ones to upgrading to the next language version.
This library has been a reason to employ me, so the monetary benefits are there.
I don't expect somebody to pay for something that I put out for free, I don't expect anybody to help me make that something better either. However, the time I've put into this project is worth a thousand times less to me than the standing and respect I gained, and the people I got to interact with so far.
It even misses the main story -- that the OpenSSL license has a peculiar advertizing clause that causes all sorts of integration problems with other projects.
[Citation needed]