I also wanted to point out this graph:
Read the whole thing.
... it is perfectly possible to conduct talk radio at a high level of seriousness, and several talkers do well at matching the quality of their shows to their intellectual pedigree. Consider Hugh Hewitt (Michigan Law School), Michael Medved (Yale Law School), William Bennett (Harvard Law and a Ph.D. in philosophy from the University of Texas) -- all three of these brainiacs have popular shows on the Salem Radio Network.