Most self-taught artists don't survive. I can only think of one that did- Howard Finster- and it only worked because it was folk art.
Van Gogh, Gauguin, Monet, ( I could go on for forever) etc.- all took classes...
Am I right that Van Gogh never sold a painting while he was alive? If so, I'm not sure that I would say that he "survived."
Thinking locally, I can name Gordie Hinds and Woody Long as two artists, who were self taught, and both seem to be doing very well, "surviving." Woody's work is sold all over the world, and he has work hanging in the Smithsonian. I know you said that "most" don't survive, but for that matter, most people change careers at least three times in their lifetime, so while what you say may be true, it really doesn't matter whether or not an artist "survives." Even if they don't, they aren't much different from the rest of Americans.