Almost all developers write code for job not for hobby.
As much as I'm trying not to get involved in this thread mainly due to my lack of ability to foresee that a block of text will solve a bunch of problems, I do just want to point out that before I joined 2ndQuadrant that PostgreSQL for me was a hobby, and I did submit several patches which were accepted and committed. I had no sort of financial interest at all in doing this, I did it for free, with the only form of reward that I received was that it made me happy when when my code was accepted. The only thing I wanted out of this was to improve my skills, and I thought working with PostgreSQL, due to it having very high coding standards was a good choice for a way to do this. If there was something being proposed here which would encourage more people to do as I did, then I think that would be a bonus. Perhaps someone may mumble something in disagreement about that though.
It's hard for me to imagine that I've been the only person to do this.