On one hand, this is absolutely correct. I think it is a bit pointless to engage in malignant moaning about the arts when the arts have never paid well. After all, human beings could technically live without film, books, or what have you. It makes sense doctors get paid more.
On the other hand, even if writing is something done on the side, it's frustrating that capitalism punishes people for not spending every waking second trying to achieve more and more financial success. Writing is not always fiction writing, but to focus on fiction writing for just a moment, it's hard to justify writing a "story" if there's no guarantee it'll make money when you need to pay for your car, you want your kids to go to the """best""" college/high school/etc., and you need to work late to get a raise. The hamster wheel of pressure and guilt about not being productive exhausts me, and I'm not broke, so I can hardly imagine how exhausting it must be for someone in an absolutely dire financial situation, especially if they're being told "poverty is the result of personal failings" in ways both big and small.
Capitalism does bleed people. Not going to argue with you there. And while most people recognize the importance of art in their lives, our capitalist society isn't set up to reward those producing it. This both reduces the number of people who can afford to produce art, and prices that art out of the reach of a lot of people.
This is why I love libraries.