Mark Davis

Full disclosure: I am a child of the Johnny Carson era. That means I grew up with the sound of Johnny’s “Tonight Show” monologues in my ears, his sense of humor helping to shape my own.

It also means that when I talk about this, I endure the rolling eyes of anyone too young to remember his era, which ended with a May 1992 farewell.

We now see the end of the Jay Leno era on that show, as the news solidifies that he will be succeeded by Jimmy Fallon early next year.

Fallon, who has followed Leno’s show for four years, will duke it out with the freshly rescheduled Jimmy Kimmel, moved up an hour by ABC earlier this year. CBS would like us to remember that it will continue to offer at that time the venerable David Letterman, who has now done a late-night show for longer than Carson did.

Any game of TV dominoes reveals what the networks think of the nation’s sensibilities at the time. So what are we to learn from the radical shifts about to befall the bedtime viewing landscape?

First, it all seems to be a quest for the “younger viewer.” What is that, exactly? Younger than whom?

I’m 55, and I think Fallon and Kimmel are both very funny. Leno has grown stale for me, but so has the supposedly hipper Letterman.

I was also a fan of the 16 years Conan O’Brien spent following Leno on NBC. I celebrated his ascent to the “Tonight Show” throne in 2009.

All six months of it.

Conan doing “Tonight” was not a ratings hit, and heaven knows, neither was NBC’s genius decision to cram Jay Leno into the last hour of prime time. The inevitable carnage sent Conan packing to TBS, where he continues to be funny in near-obscurity, and Leno back to his “Tonight” show stage for a few final years.

The NBC decision to “go young” with Fallon must drive Conan nuts. There he was, with far more youthful, edgy humor cred than Fallon may ever have, banished to basic cable. Now, Fallon gets one of the most venerated titles in TV history.

None of this is to speak ill of Fallon, who has surprised me greatly. When he was announced as NBC’s successor to Conan, I remember joking that Chris Kattan must have been unavailable.

But Fallon has proven to be far more than just a worthy “Saturday Night Live” alumnus. While his interview skills need honing, his prepared bits are among the best in the genre, boosted by his uncanny gift of mimicry.

Fallon will host from New York, meaning all three major network shows will have an east-coast flavor.