With social media, the cost benefit analysis doesn't deliver marginal results, just less stark/concentrated results. Drink driving is self evidently bad even though 99 times out of 100(?) it does no harm, because one time out of a hundred its consequences are catastrophic. Social media on the other hand is harming essentially 100% of the population in initially milder ways - even if you don't use it you're forced to live in a dumbed down society where wealth and power is becoming concentrated in the hands of those who pedal digital dopamine and in a democracy being undermined by disinformation. Of course 'initially milder harm' is step one in frog boiling.