It has nothing to do with popularity. It doesn't really have anything to do with money either.
The fact is that 98% of what people make sucks, the stuff on the radio is just more accessable to your ear.
And when an artist becomes famous, they usually can no longer self critique their own work.
They start to believe the hype and what others are saying about them and think that they can do no wrong when,
in fact, they are still fallible humans like the rest of us and still make a lot of crap.
Artists get lazy and their labels know that people will buy on past experience, so the once famous DJ stays famous by virtue of the crap they put out.
The business of music is about appealing to the widest possible audience also so they stop trying to innovate because people like things that don't change
- like GOA...