Back in the 90's we were somewhat supervised when using the internet on the family PC. We were also somewhat supervised while watching the family TV.

Good point. There was a technology shift in portability and cost which meant each individual got a personal computer. They went from the common areas to personal spaces like bedrooms.

Maybe a lot of issue could be resolved by just having a phone that has to be in a common space, using a technology like LiFi [1].

[1] https://en.wikipedia.org/wiki/Li-Fi