I've likened it to the guys from Def Leppard advising kids of today how to have number one hits in America. These people aren't exactly idiots but they are hugely deluded about their own popularity and understanding.
— Dan Davies (@dsquareddigest) February 12, 2020
The joke is that everyone is fighting the last war, but this is especially true when you won the last one. Or maybe 3 wars ago. You are a brilliant general, even if you haven't commanded any troops lately or done much else other than show up on cable news on a regular basis and collect rents from various projects you have lent your name to.
When a new administration gets into power - Clinton 1993, Obama 2009 - they bring a lot of younger people in with them because everyone who does the work in DC is 23. But those people age, and a new party gets in power, and there are no opportunities for a new generation of young people, until some of them help to win a war (campaign). Until then, we have Def Leppard, or maybe the Dave Matthews Band, telling us how everything works.
Times change and everyone loses the plot. Politicians themselves are old generally, of course, but the people involved in their campaigns and then running the show aren't. Not necessarily, anyway. Some names never seem to disappear...