I think a lot of people never gave Leno a real chance, but once they saw him when Hugh Grant was on there, they realized Leno was funny.
In regards of Carson/Letterman - It was NBC's show, not Carson's, and NBC was, and still is trying to target the younger audience, and Jay brought in younger viewers at that time. I'm not sure if he is now, but back then, Jay was the guy younger people wanted to watch.
This is just an opinion, but Letterman has always had an old people vibe to his CBS show. I watch his show sometimes, and for years, I seriously feel like I'm back at my grandparent's house.
And with nothing but the highest respect to Johnny Carson, towards the end, his show was a Grandma and Grandpa show, which is why NBC kept hinting for him to retire.
I don't wanna come across as bias, but since I was a kid, I felt Jay's show had that young vibe to it. Maybe because the lighting on his show is darker, and it gives it a nightclub vibe to it, and even the colors are nightclubish colors. Whereas Letterman's lighting is all big and bright, like a bingo hall....
....Plus, Jay has Kevin and his mostly all black band, and black people (no matter how old they are) are rad.
