> Anecdotally, I know people in their 20s who use TikTok daily, and they're no longer able to watch a movie without losing focus.

I'm almost 40 and haven't been able to do this since the smartphone arrived; it's not Tiktok, it's just that the phone is right there, and movies are slow-paced (arty thrillers) or monotonous (lengthy CGI fight scenes).