Porn was perhaps a bad example because I don’t think evidence suggests conclusively that it is addictive.

But take gambling.. gambling is considered addictive and its disorder classified in the DSM-5. (Gambling is probably also most like TikTok/Instagram in terms of activating reward seeking and pleasure in the brain). In the US we do heavily regulate gambling and some legislations have required warning labels for the risks involved with gambling.

So no, if would not be unreasonable to me if we as a society discussed potentially regulating social media in some way.. be it as non-invasive as warning messaging.