First of all, this isn't enshitification as defined by Corey Doctorow. This has nothing to do with an internet platform getting worse because the priorities of the proprietors changed.
I don't think it's entirely fair to blame Google for this. None of these companies do this for entirely altruistic reasons. At the core of the problem is funding in education. Google saw an opportunity and jumped on it. When given a choice that kids get no computer hardware vs. dumping price Chromebooks I would still vote Chromebook. Get your politicians to set aside less money for tanks and more money for education.
Besides, no one is stopping kids from exploring other platforms. Google is looking for an infrastructure lock-in, get them locked in while they are young, but you can go do other stuff. It's also a question of financial means and interests. And they don't need to do LAN parties because they already have Fortnite and stuff. Life moves on. Your childhood was also markedly different from your parents'.
In no situation where weed is legal minors are allowed to buy it. I would be onboard on this propaganda train if all I saw on Netflix is 15yo's getting high. Which I don't see that much really.
Minors should not consume it. Minors have parents. Minors' parents' job it is to keep them away from that along with sniffing glue, tobacco, vaping, alcohol and eating laundry capsules, just to name a few dangers more.
The negative effects on brain development I read about were all linked to regular, if not heavy use. There is enough wiggle room for school/education and, once again, the parents to step in.
Idiocracy is happening anyway.