Or, overcrowded underfunded school systems who have change curriculums in order to make education fail because it puts more money in the pockets or specific individuals.

Lots of things contribute to the poor mental health of the general population including students. Phones are just the newest scapegoat and instead of actually regulating what they can show all of us, we're pretending if we just stop kids from viewing those things it'll be better. Meanwhile the same shit being posted all over social media is present in all media including ads, television, and movies.

This crap doesn't have to be in schools to have a detrimental effect.