It's just like a lot of people say to comic book creators or novelists or screenwriters when they're afraid to submit their work on spec because they're afraid their "genius" idea might be stolen...
If all you got is one good idea, the creative field is probably not for you. Ain't no new ideas anyway, there's probably fifty people developing more or less the same idea. Your ability to generate compelling commercial art should be a continous talent that you've developed over years of practice and learning, you know? If one of your ideas are stolen but it gets your foot in the door to ply your talents, that puts you ahead of 99.999% of people who wanna be commercial artists and/or craftspeople.
If you're any good, you should be able to pull fifty songs outta your hat, not just have twelve that it took you twenty-five years to come up with. Everyone has ideas. People without the ability to execute ideas sometimes have great ones that go fallow. What one is judged upon is the ability to follow through on the execution of any number of ideas, good or bad, with your personal style and skills and talents and whatnot.
I think. I ain't been paid shit for nothing because I am afraid I am completely untalented. About all I can say for myself that it isn't because I belong to the false cult of the muse.