I'll bet I'm not the only person saying this, but maybe you're reading it here for the first time: Jay Leno is probably washed up. He's a remarkably resourceful comedian. He was amazing during the Writers' Strike. But his show is very set in its ways, and a lot of his viewers are just kind of “used to it.”
Leno was THE choice when he inherited the Late Show mantle and ran with it. Now, he's the guy whose same show failed at 10 p.m.; he's the guy who is chasing Conan O'Brien away, even though he doesn't seem to intend it; he's the guy who wants his late time slot back, even though he's forgotten that he gracefully released it. When he returns to 11:37, a lot of his taken-for-granted viewers will not be pulled to him by the old trigger. He'll have to be very imaginative to rebuild a big audience. Jay, and NBC are turning back the clock in a world where the clock is running faster and faster in the opposite direction.