I'm old enough to remember Steve Allen hosting the Tonight Show during the 1950s. I couldn't watch it often, because I was too young to stay up that late routinely, our single TV located in a parlor where I'd be seen, but every now and then I'd manage it, on a non-school night or some other special occasion.
I was watching the show fairly often when Jack Parr hosted it until 1962 (by then I had a TV in my bedroom, something of a luxury in that era, even if it was only B&W). One of my favorite Parr guests was the eccentric genius Oscar Levant.
When Parr left the program there were a number of guest hosts, including Jerry Lewis, who brought absolute insane chaos to the show. The selection of Johnny Carson to be the permanent host was greeted with skepticism, since at the time all he was doing was a minor afternoon TV game show on rival network ABC, called "Who Do You Trust" with Ed McMahon. He wasn't considered a "heavyweight" at all, but the choice turned out to be inspired.
Watching Carson, I would often think of his youth on the bleak Nebraskan prairie in the 1930s, listening to the radio legends who ruled the airwaves back then, and watching the movie stars on the silver screen, him dreaming of someday being in that world, a million miles from his own. And then, one day, he had the most popular nighttime show on US television, and the same idols from his youth all came to be his guests, and to fawn over him:
... and countless others
I can't begin to imagine his feelings when those living legends sat down with him on his own show. What a wonderful life that was.