One of the challenges of the writing + money conversation is that not all writing is equal in the eyes of the market. “Writing” easily comprises several dozen different industries, and each values (or pays for) writing differently.
When it comes to creative writing by people who are primarily engaged in art-making—Literature with a capital L—history shows that it’s often been a poorly paid endeavor for the majority. There’s always been a small and limited audience for Literature; the audience for it hasn’t declined (at least I would argue), and here’s a good piece that expounds on that (from the perspective of journalism, but same thing applies to poetry, short stories, and so on):
Writing for a living, if that’s the goal, means paying attention to market demand and value of what you’re producing, and likely making some compromises as to what you produce. It’s not possible to guilt the market into valuing or paying writers, especially when there’s an oversupply and few readers—although some governments are far better than the US in their arts support, and subsidize it as a culturally important activity. But that’s a different thing altogether than expecting the market to pay for writing whatever you desire. (And we haven’t even gotten to the part where more and more amateurs are writing and producing than ever and have no thought of payment or career.)