Chrissy gets about 15% of Rush’s ratings in any one day (and that is probably being very generous). It would take him several weeks to be considered relevant ‘cause it would take that long for him to say anything worth listening to (still unlikely).
Rush practices broadcast excellence every day and is heard by many many more people with a brain.
you can’t really compare a radio show with a cable tv show. Also, Chris (and this is also true of Bill O’) is able to reach a demographic that can make or break any election: the middle.