They don't need to make a living. They're already making a living by doing some other job, probably a boring job. They're writing because they enjoy writing, and there might be a financial payoff, but it's certainly not something they're banking on. It's just like aspiring actors; they work as restaurant servers to make a living, hoping to become a big star. It's not really a good career move; if you want a low-risk high-paycheck career, you do something unglamorous and boring, like writing software, or some other office job that requires a college degree.
May I then suggest that all software developers also should forego their paychecks and work for free, since they love programming and should do it in their spare time while having another day job? For example in a restaurant.
