This is absolutely not true.
Here in the UK schools are swarming with ipads and shit like that. They're given to primary school children because they're "more engaging". Children are supposed to practice their reading and even handwriting[1] on ipads. Naturally they're on youtube instead. It's really bad. As far as I can tell, private schools are even worse. Currently the only way that I know to escape this is homeschooling.
Saying "it's a solved problem" is incredibly dismissive to parents who do everything right in their homes, but then send their children to school and schools exposed their children in this way.
Saying that phrase in such a definitive manner caters to the interests of the companies who push these shit onto schools. Please stop saying it, it's harmful.
[1] leaving this reference here because I'm certain that people without school aged children won't believe this is actually true: https://www.letterjoin.co.uk/