It's difficult to figure out why the push-back against Rush Limbaugh finally reached critical mass after all this time. There might be an unspoken factor behind the Rush Limbaugh self-destruction: his aging.
The sight of this old man demanding a young woman's sex tape is enough to turn off anyone. Followers want their leaders to be better than they are, richer and more attractive. (The richer you are the less attractive you have to be.) Once conservatives no longer want to fantasize about having your money (or you), you're toast.
And Sarah Palin is about five years away from having the same problem. When your popularity is based on a fantasy, it only lasts as long as the fantasy lasts.
ADDED: Digby discussed this as well.