Most of the assumptions you've made don't apply to me, a 40 year old father of two. It may very well apply to some people similar to me. This is the problem with stereotypes and the problem with people perpetuating them. Oversimplifications are a shoddy mental crutch to deal with the complexities of reality.
The older you get, the more experienced you become, the better decisions you make, the more valuable you become.
At 22, I was a great tactician. I could code faster than anyone else.
At 32, I'm a moderate strategist. I code slow than when I was at 22; but my productivity is far higher.
At 52, I hope to be a great strategist. The potential is frightening.
3 hours of sitting thinking about a problem, then 30 minutes of coding. I would never have done that at 20, I'd have opened an editor and started typing because I was still learning the intricacies of the platform.
In my late teens/early twenties, I just implemented the first thing that I could think of.
Back then it was much easier.
Actually, I have noticed that other developers around my age still think like I did when I was in my twenties. Maybe it's because I've been coding since I was 10 (22 years!) and full time since I was 17, and most came in after university?
Then there is the argument about blindly learning to code from BAD code on the internet, whereas we had to learn from books! :)