But they are arriving at the fight in a weaker position than usual. In a polarized world, their failures around child safety are increasingly the one thing that partisans of every stripe can agree on. Regulators are no longer impressed by the bare minimum. (They have teenagers of their own now, and all the screen-time battles that come with them.) I don’t know which trial or regulatory action will be the one that finally forces major changes to social platforms for teenagers. But it seems increasingly clear that change is in fact coming. And for the first time, some subset of users will find that the feed they are scrolling through suddenly comes to an end.