A couple of things spring to mind after reading this thread. Just because you're not signed to a major record label doesn't mean your music isn't good enough to sell. You've *heard* some of the music that gets used particularly on TV, right? But just because your music's good enough to sell doesn't mean anyone's going to buy it. It's always been the case that the people making a living from music represent the tip of the iceberg of musicians. A combination of luck, temperament, looks, persistence and other responsibilities all come into play. That's true now more than ever with access to affordable recording technology.
It depends on what you want from your music I suppose. Of course, I'd love to make my living from making music, and it's what I'm always aiming at. But I'm also realistic enough to know that this may never happen, or I may only make a small part of my living doing it. In which case, it would be nice to think it could at least pay for itself. If I can't even achieve that, I won't stop being a musician. So long as there's someone out there who enjoys what I'm doing, it's enough (I hope) to keep me motivated. Look at some of the classical repertoire. Many highly regarded composers lived in great poverty during their lifetimes, only for their music to gain recognition long after they'd gone. Not saying that will happen to me, but what I am saying is that revenue is no indicator of quality.