Yes, he has lost some popularity and revenue, but he is essentially a purveyor of a very popular line of goods facing the PR challenge of a product recall.
There are plenty of others willing to take up the slack of supplying bigoted BS.
The question is: what is fueling the demand? While there is a certain percentage of genuine sadistic thugs in any society (see Clive James' historical argument for this in his essay an Terry Gilliam in the book Cultural Amnesia), I don't believe that it is big enough in th US to make up the combined audience of Limbaugh and his fellow cowards.
It takes the right circumstances to bring out the exploitable worst in people. Right now, we face the end of an excruciatingly long and useless war which gained us not even the illusion of accomplishment, plus an economic crisis no one seems to know how to fix.
The result: frustration. We want to see something, anything get done.
But nothing of substance can get done. There is no money to spend, and those who should pay their fair dues shout patriotism from open mouths but deny their country with closed wallets.
Enter social issues.
Making prejudice policy is easy. First, it costs the taxpayers little directly (though the hidden financial burden of dividing the citizenry is huge: it takes a lot of money to build, maintain and man barriers).
Second, it plays to deep human instinct. Behavioral economics provides ample evidence that we are not the rational creatures traditional economics would like us to be (I will provide references when I can).
Given the choice between one salary that is comparatively greater than those of our peers, and a slightly higher salary that is comparatively less, most people choose the former. In other words, we would rather have more than our peers than more for ourselves.
Worse, recent experiments entailed giving students a dollar amount from 1-10, and then having them distribute and additional 2 to either those who originally had either 1 dollar more or less than they did. Those students who originally had 2 wore more likely to give to those who had 3 than those who had 1. If this works on a societal level, it would mean that we would rather the rich get richer if the alternative is that we switch places with the poor, even if our finances remain unchanged. The situation is arguably worse when the disadvantaged are seen as somehow different, say, because of complexion.
Propagandists understand these instincts on a deep level, and tap them to promote their agendas. Magicians know how to exploit blind spots.
It's called "baiting" for a reason; it lures us. The metaphor is extandable via the image of Neil Gaiman's character Despair, whose symbol is a hook.
As long as we continue to maintain a situation in which no forward movement is possible, those who peddle backward movement will be able to profit by landing customers with the hook of desperation.