Why are teenagers stupid?

Why are most teenagers stupid in some way? They have brainrot and can’t take responsibility, they care about stupid memes and games, and know nothing.
Why?
In my opinion they are raised like this, in a society that treats a 15 years old like a child who can’t take responsibility, and he grows with friends who are just stupid like him, on phones most of the time, so he and his group of friends are being brainrotted and they all enjoy it, and no ond tells them that its wrong, and most parents don’t care, and additionaly a (mostly) failed school system.
Whats your thoughts?