I have two diverging responses to this - one, if they're credited for their commits, in the purview of FOSS projects, they're compensated as much as they expect; two - that said, I would love to see FOSS projects get more love and financial support from the community - which is why watching the GODOT project has been exciting. I'm not much of a dev, and not in a position to contribute to what they're doing in code, but sending them some coffee money has been worthwhile.