I agree with you, American schools seem particularly bad at breeding these sorts of unhealthy dynamics, and we shouldn't accept it as normal. But even in a better environment, unstructured social interaction with peers still seems like a useful part of growing up/socialization and shouldn't be replaced with kids sucked into their phones.

I think USA does everything later than in other countries.

So I think by the time I got to high school we were too mature for the kind of bullying you see in USA films, but that did happen earlier.

I've had plenty of friends I've only known through the internet and a chat room. It's not the same as being in-person - I don't see a way to reliably turn out healthy adults unless kids talk to each other.