Interesting thought. If TikTok got banned they would probably release a web interface for Americans or Android phones would suddenly become really popular among teens.
The other year, teens were surprised when they got a green bubble on their iMessage, indicating the other person was not using an iPhone.
Admittedly, TikTok does appear to be more fun and interesting (for teens) than Instagram, Twitter, or Facebook, because the point is to just watch fun and pointless stuff. And maybe learn something new, or do something yourself to imitate them.