During the '90s, a lot of us in the indie film world were not making our money off our movies. We were screenwriters doing scripts for hire for studios.
You end up giving up half your salary every time you make a movie because you need the money to make the movie you have in your head.
You still get the movies made. A filmmaker can always scrape up money to do a movie. The passion drives it. And you'll get the money. Money's the easiest thing. But the hardest thing is finding a way for people to see your movie.