The how part is interesting to me. In many jurisdictions a bartender can be charged if they over serve a patron. Maybe something similar could be applied to services like Instagram and Facebook?

Their metrics are driven by advertising goals. Maybe limit the number of ads that can be shown to a user in every 24h period? If Facebook were only allowed to show ads for the first 30 minutes of any user’s session per day, a lot of the incentives for addictive design are reduced.