I'm responding to this comment as a response to all the comments which all seem to have a similar tone. I think it's important to remember that kids are at a different stage in their life than adults. Having small locked in social groups from a young age is bad: it limits experiences, creates echo chambers, and ultimately can lead to stunted growth. The most important thing about what you said re: kids turning into adults is that they had the chance to select their 10 or so folks from a massive friend group. Locking in a social group when your choices up to that point in life are the people you went to elementary school with is likely to have severe consequences, and that is the real harm of shutting in-person schooling down.

I won't even touch on the idea/harm of replacing physical connections with purely online ones. A lot of my friends are people I have met via the internet, but our friendships have often been cemented by eventually meeting up in person. I suspect the same is true for most people who talk about their extensive online social graph.