Well, who knows what they will be doing if it is not Tiktok. Hopefully they will pick up a book, but doubtful. They need a way to communicate with their peers.
I'm not seeing how this stops kids from communicating with their peers. That seems like a bad-faith argument as they can send an SMS, make phone calls, send emails, meet in-person, play video games, etc. The things many of us grew up doing with our friends.
Why do these services have to lose? That's a choice made by this country's government. They can change it.