Why do people write books that say it's better to be older...

Why do people write books that say it's better to be older than to be younger? It's not better. Even if you have all your marbles, you're constantly reaching for the name of the person you met the day before yesterday ... If you work, you're surrounded by young people who are plugged into the marketplace, the demographic, the zeitgeist; they want your job and someday they're going to get it.