Rush et al is an institution that has been groomed and tended for many years. It takes time and perhaps some general luck to become widely heard and influential in a free market environment. Startups fail all the time even when they do have something valid to say. How the Left does not grasp this is beyond logic.
Rush is outstanding, he knows his audience, he has mastered his craft and the issues he pounds. He was also helped ALOT by having Clinton in the White House for 8 years and a continual choice of issues to select. Still, he has maintained his audience even through the Republican controlled years.