I disagree with this. It's not that someone has to pay the developers of what you refer to as Type 0 open source projects for the incentive to exist for them to

I disagree with this. It's not that someone has to pay the developers of what you refer to as Type 0 open source projects for the incentive to exist for them to maintain it; it's just that the developers have to have a reasonable expectation that some value will come to them as a result of of maintaining the project. Everyone values different things, but if money is the goal, I think developing popular software in the open is as good a way as any to attract a healthy financial offer from potential employers.