Ban the hardware, not the software.
So, are you suggesting that the legal use of smartphones should be banned for anyone under the age of 18? What kind of society do you want to live in?
1. a "small" device that a person can use while moving
2. cheap/free internet access (wifi and/or mobile data)
3. high fidelity display with high refresh rate
4. a camera (I would probably group this together with 3)
Disabling 2 or 3 of those would short circuit the delivery mechanism of the "opioid" while still allowing the device to fulfill its more "useful" purposes.
Examples:
- A small internet device without a hi-res display _and_ a camera is still useful for "knowledge at your fingertips", communication, navigation, payments, etc.
- A device with a hi-res display, with a camera, with internet access, but not "small" is either a laptop or a tablet. That breaks the mechanism of one-half of social media addiction, which is the capability to instantly create and upload content right on the spot. (Although I would argue a tablet will still have that problem)
- A camera that doesn't have internet access can still allow a user to record events, but uploading the content will have to be delayed to a later time. A fair trade-off in my opinion.
And this is all possible with current hardware, by extending Parental Controls to disable the camera, and/or internet access, and/or handicapping the beautiful crown jewel displays.