The old model was that people who enjoyed creating made things. Copyright, starting around 1890, changed that to be about profit above all else. It’s telling that you can’t imagine writing a book if there isn’t the promise of money.
If you can’t feed yourself writing then you have to have a job, which means you won’t have nearly as much time (or energy) to write. Writing long form work is a very long, draining process. That’s why it’s a full time career for many.
I’d love to shoot documentaries I care about all the time but if I’m not getting paid it simply isn’t viable.