Bill Carter takes us back to 1989, when CBS was promoting Pat Sajak as the new face of late night, the man who would go down easy with viewers if and when Carson retired--if not for that meddling Arsenio and that Dog Pound (on many of the same CBS stations at 12:37):
In fact, Carter hints that Sajak's failure led to Letterman moving to CBS and Leno getting the Carson gig (although it could be said that Arsenio was the disruptor in the whole thing).