Don't knock crystallized intelligence.

In my 20s, I could learn a programming language in a weekend by reading a book. I could write code fast. I could figure out bugs. I felt so fast and so smart.

In my 40s and 50s, I looked back at that guy with some amusement. Sure, I didn't type as fast. But I spent a lot less time debugging because I wrote it right the first time, because I could just see what the right thing do to was. Net result was that I produced working code in less time. 48 might have been my peak year.