But the ability to show ads is the only reason to allow the youth on the apps. Remove the commercial reason for brainwashing kids, and the rest will probably sort itself out (I guess is the logic)

Addicting kids to the platform such that you can show ads to them when they turn 18 seems to have obvious value.

To some degree. But addiction describes a range of behavioral symptoms with a variety of durations and dynamics. The expected return of designing platforms to entertain 17-year-olds will decrease a little, but the expected return of designing a platform to entertain 13-year-olds will decrease a lot. By the time the latter group is monetizeable, they might move to a competitor's platform — just as prescription painkiller addicts have an easy time substituting heroin when they find it's cheaper.

One thing that's particularly convenient for regulators in this case is the tendency of adolescents to deliberately change their behavior as they approach adulthood in order to reinforce a sense of personal growth. 18-year-old me didn't want much to do with games and movies for 13-year-olds.

The problem is what is an Ad? Is the Cryptobro shilling for the coin of the week an Ad? is the Influencer that "casually" is using her brand of Mascara while talking an Ad? Do creators need to have two versions of the same video (one with promotion, one without)? Most ads now are difficult to tell apart from content. Is this review really a review or content length ad?

All of those are quite obviously ads and must be clearly labelled as such already within the UK and most of the EU.

Ads have everything to do with because they are the incentives shaping social media.

> will not prevent....

While "first drugs are free" is not unheard of, e.g. "gratis" licenses for schools, I think you vastly overestimate the willingness for long term investment. E.g. if the law says "no ads for under 18", they might stomach the costs for 16, 17, but starting at 13? 5 years of "gratis, adfree"? No change at all? You think so?