Modanung, you mentioned that if I should find those devs, I should send them to FGD; I found several. Not all of them do free software; some might be willing to do so if we form a community were this is appreciated, but I'll have a hard time to recruit people onto a board and convince them to put their stuff under open license. If we open up FDG to closed source games, we can do this - but I don't believe that this is what you want. Uniting with others means to take steps towards them.
About the commotion of underground and illegal adressed by Lopy and Peter: Underground Art/Movies/Literature are a standing term, check https://en.wikipedia.org/wiki/Underground_art . It's not about illegal stuff, but about counter culture. However, if we manage to find a better term I'm alright with it. But I just googled; most who use these term by now (not many) are legally operating clans.
About the problem of self-exploitation, I allready wrote a few lines ("Practical Questions"):
Make non commercial games. This doesn't mean, however, that you can't take money for your games. Non-commercial gaming shouldn't mean self-exploitation. Using the option to make payments voluntarily, offering a way to compile the game from source while offering a paid binary, offer to exchange it for other games or media done by other underground artists, or - as a minimal definition - by not using any money as a budget that isn't your own while not trying to make a noteworthy revenue from your own investment of time or money could be good boundaries to set. This should be discussed in detail within the community.
However, keeping the really commercial players out is important. If we let them do as they want, they will use their greater market force to push the hobbyists out of sight - just as it basically happened within the indie game dev scene.