Why would I, a right wing libertarian, lend my time to developing a piece of software that I am unable to make a profit from? I have no motive.
Because you do stand to gain regardless. "I have my code on the source of <major FOSS project every tech guy has heard of>" is like. Amazing portfolio material for any job interview. I had a friend get a job in the games industry (though they regret it to this day because the game industry sucks--) with nothing on his resumé except for a smattering of mods for popular games.
Any pro-capitalist person with a functioning brain will acknowledge the role of non-monetary "Profits" in every human relationship, yanno?