I think art can have value without being particularly saleable. And with certain kinds of art, the fact that it's popular and lucrative may even be a sign that it's crass and inauthentic. Think Damien Hirst and Andy Warhol.
Then either the art you admire is way out of your price range (I admire Alphonse Mucha, but I don't own any originals!), or the artists you admire are doing a poor job of letting you know that their work is affordable, and would add to your quality of life.
Exactly!
An artwork is not a porsche. Even if I had anywhere near enough money to buy a Kiefer, there would be no room for it in my house, and it would not belong there anyway. I think it is valuable simply that Kiefer's paintings exist, and would be even if museum's weren't willing to pay for them.