Dick Cavett, who knows a thing or three about late night talk shows, writes about the early days of J. Carson on The Tonight Show. He's quite right that they didn't go swimmingly and that many thought NBC had picked the wrong guy to succeed Jack Paar. Johnny did get the numbers though and eventually, he won over the critical voices that argued that Merv Griffin would have been a better choice.
Cavett refrains from mentioning it but among the reasons later on why some did not recognize Carson for the class act that he was…was Dick Cavett. I remember a time when Cavett, over on ABC in a competing time slot, was the witty, urbane guy preferred by critics and Carson was a hayseed from Nebraska whose only skill was nudging starlet guests into saying naughty things and then he'd make a face to the camera and/or utter some cheap double-entendre. Carson's stature now as the Undisputed Greatest Talk Show Host Ever was late in coming and only really solidified when he announced his retirement. Once upon a time, his ratings victories over Cavett were prima facie evidence to some that America was a nation of dolts.
In this and other recent articles, Cavett quotes Johnny as having second thoughts about his decisions to relocate The Tonight Show from Manhattan to Burbank and later to trim it from 90 minutes to an hour. I've no doubt he said those things to Cavett but at times, he said the opposite to others…and he had it well within his power to reverse both choices and didn't. Personally, I always regretted the change to an hour because it eliminated too many guests who weren't there just to plug their new movie. The conversations all seemed more rushed…more eager to get on to the punchline. The trend on talk shows away from conversation to recitations of pre-interviews didn't start with Jay and Dave. It started when Johnny went to an hour.