If we instead imagine a world where parents allowed, even encouraged 60% of children to smoke, and there was no clear route to outright stopping them, giving them at least a better alternative that doesn't hurt them as much would be worth considering
I think it's still better to ban these obviously harmful things and to reduce exposure to them as much as possible.
I agree that if a parent is dead-set on giving their kid endless screen time, tobacco, or heroin, they will find a way to do it. But the tobacco story demonstrates there are many interventions that can significantly decrease the net amount of abuse. If you want to take a public health argument, do it honestly.
Screens or tablets aren't the harmful drug in this situation, they're the needle. A needle that can contain medicine or heroin. The harm is from specific apps and social media. A device can be locked down. You can control what it's able to do and how much. I've used screens to teach myself a language to fluency, a hell of a lot about software development, and countless other things.
Would you object to a tablet that could only access Khan Academy, Openstax and Udemy? What about if we added on a 20 minute allowance of social media? I haven't looked super deep into the Amazon device much but it seems this is the direction they're heading with the parental dashboard
"Educational content has to come first. Your child completes reading or learning goals in Kids+ and educational apps before entertainment apps unlock"
I mean obviously kids are going to try to game the system to get to what they want.. but it seems like a reasonable path to test, and it doesn't require trying to turn every bad parent into a good one, or do something outlandish like ban tablets