Not all commercial music is bad. Music is measured through the tests of time. As time passes, people see music more for the sound and the memories it provokes, rather than the image surrounding it. Example, I don't hear Britney Spears anymore. Shows you what crap it was. However, no matter how much one detests bands such as Pearl Jam, Nirvana, their musics has passed the barriers of time. Their songs are still played on the radio. Hell a great band like Led Zeppelin I would define as commercial music. But it is good, and stood the test of time.

Commercial music is just music with a spotlight on it. It changes constantly.