Problem is this only works if nobody else in their peer group has a smartphone either. So the more I think about it, the more I reckon there's only one solution.
Governments need to age-restrict smartphones, and forbid possession under, say, 16 or 18 years of age.
Sounds very extreme, but we have a long history of successfully doing this for other damaging, addictive things - so why not here?
At this point we have more than sufficient evidence of how incredibly harmful smartphones are to adolescents, and it's time to act.
Smart phones were not around when I was a teen, only dumb phones but I had a dumb phone starting at age 15 which I paid for by working and used to let my mom know where I was and when I would be home.
At 16 I worked a PT job and had a car, sometimes I went right from school to work or my job would call and ask if I wanted to work and I would call my mom and tell her I would not be home after school. I would call and let her know I was going to my boyfriends house if we were both free. I graduated HS at 17 and started to work FT and right after I turned 18 I was engaged but by your logic even though I was done with HS at 17 and working FT I was too young for a smart phone?