his show was subsidized to start and they bought up stations for him for the purpose they use him for now.
he's a keystone piece for any talk station he's on and a national propaganda operation that does not operate to make money, except incidentally and to pay overhead. his true worth is to get the 1% where it is now. but that is not the market calculation that most people make looking at this, they think he was paid for his wit and wisdom and selling flooring and hair tonic. that is not why he dominates. what the 1%'s think tanks really pay for is his nationally broadcast royal lie-detector-beating certitude and ability to rationalize opposites within minutes. the fact is that the monopoly makes it really hard for progressive talkers who have proven they can beat him to even get a shot. there are many cases of blue area with no progressive talkers but overlapping limbaughs.
i'll bet what is much more significant in the calculation as to whether limbaugh is profitable and ubiquitous is that many of his biggest stations piggyback university and pro sports. take those universities away from them, and they should be soundly shamed, and i'll bet the whole RW radio monopoly is a huge bust.