Musicians tend to be intelligent, disciplined problem-solvers, though, and versatile enough to make a living one way or another. First, consider that a musician by definition is a performer. Composition is perhaps even more difficult to earn a living in than performance. Very few composers of art-music make it big, and most struggle just to have their music heard at all. With electronic music in such widespread use, a lot of commercial work that used to be done by highly-trained, skilled composers and performers now goes to someone who can operate an electronic keyboard and other MIDI equipment.
Some composers are able to make a living by writing for television, radio, or film.
However, this is also a difficult industry to break into. Teaching private lessons is a good way to supplement one's income. With luck, you could build up a private studio large enough to pay your way through college. I find it a very satisfying outlet, although, I accept only a limited number of students. I know people who support themselves by teaching 50 or more half-hour lessons per week.