I agree with some of the comments that it's not necessarily phones themselves, but I disagree that the culprit is simply social media. Any app on their phone is going to be geared towards keeping them locked into the experience, because that's how apps are built.

Full stop, I don't want anything manipulating my child's attention. Because as I'm getting older, I'm realizing that the most powerful tool you have as a human being is your ability to focus on a task and see it through to completion. Digital media of any kind has a perverse effect on that ability.

Parents of the 50's were too simplistic with their mistrust of televisions, but they had the right intuition. Digital screens are avatars for daydreams, and to dream too often is to drain your life of its most precious resource - time.