> This is a depressing thought to consider in (linear) middle age, but it is hard to escape the feeling that it is essentially true. Childhood memories have an intensity and a vibrancy that it is difficult for the rest of life to match.

This is just not my experience at all. I had a great childhood, but ask me about the most vibrant moments, and very few of them came before I was 18. The births of my children, my wedding, meeting my wife, lazy afternoons in college...

The one thing that childhood memories usually have is protection from the “real world” - looking back you realize that exciting vacation to a national park was because your dad lost his job that summer and couldn’t afford anything more, but had time. For you, it was amazing, but probably not as much for your parents worrying about where the next job would be.