He is making the point that in your lifetime you experience a long procession of politicians and other celebrities who are thought important for a while and are then forgotten. That is why, as he says later (twice), he is not interested in reading thick biographies of formerly famous politicians.

I think some commenters here are missing the intended tone of the article. It's supposed to be a confection, an amusing and self-deprecating defense of his old-fangled preferences, with a melancholy tinge about running out of time (the author is in his eighties).