I haven't seen that many TikTok videos, but I haven't seen many that didn't have music in them, and I don't think any of it was original.
Licensing music has never been easy, and I don't get how two guys (even from silicon Valley) were able to do it from launch.
Maybe TikTok comes from China because Communist ideology still influences the Chinese; or because they didn't have a Dick Cavett and a Frank Sinatra, celebrity TV. The ceremonies for the 1980 Moscow Olympics had no celebrities, but a diorama of the dozen Soviet cultures from the Ukraine to Kirghistan. The 1984 Olympics in the US had Lionel Ritchie. But Communists or not, the early promise of the internet was that you could participate, and it doesn't feel you can participate on Twitter.