Patreon is another good example of how to survive if there are a decent number of people who genuinely like what you do. See Cara Ellison and Zoe Quinn, for example. It won't make you rich, but that's very much the point.
Also, people whose writing is good enough have the opportunity to leverage their web audiences into purchasers of paid books. For example, Joel Spolsky (joelonsoftware.com) and Michael Lopp (randsinrepose.com) have published books based on their web postings. If you have content that is consistently interesting, people might actually pay to read it. And Spolsky's unpaid writing on the web also paid off through increasing awareness of his various business ventures. Ads aren't the only way to get a return on your writing investment.
Patreon is another good example of how to survive if there are a decent number of people who genuinely like what you do. See Cara Ellison and Zoe Quinn, for example. It won't make you rich, but that's very much the point.