I'm a professional artist and writer, and frankly, the things you say are both right and wrong.
First of all, those 'starving artist' art sales you see advertised on TV and that tour the country are complete bullshit. What is being sold is assembly line art. 8 or 10 people on a line and each one is trained to paint a particular part of a painting. Artists may be involved, but not in any way producing art.
I'm not sure how you decide liberal art is worthless, as most artists ARE liberals. Either way though, while it would be nice to believe that talent will out and people buy what they think is good, it just doesn't work that way. People buy what some critic TELLS them is good. Which doesn't necessarily mean creative or talented, and in fact, often means crap.
I'm an illustrator. I work for money. And yes, most art IS a business. So is writing. And in writing, the reader doesn't buy what's good either. In fact it's such a weak business these days, controlled by people who do NOT love reading, that a LOT of book that are genuinely good don't get published because the big companies want book which are either copies of other books that sold well or that they feel are guaranteed to make money. Same is true in the music business and the movie industry. And yes, before you ask I do have books published, art well published and a movie in post waiting for distribution. So I'm not entirely inexperienced here.
In commercial art, such as illustration, a lot, in terms of success. is dependent on who you know, what contacts you have, what links you make, who sees your work, and how professional you are in terms of giving the client what they want and giving it to them on time.
And I'm sure you do sell happy paintings. And good for you if you do. Putting anything positive in the world is an excellent thing. I genuinely mean that. But don't bitch at other people whose art is, perhaps darker or more depressing than yours. The proper job of an artist is to hold a mirror up to society to show them both the beautiful and the ugly, to say 'this is wrong', to make them think about those things, and feel for them.