To be fair, Youtube VS TikTok is mostly the wrong comparison.

Tiktok is mostly competing with the Insta/Facebook I need distraction so I'll let myself be numbed with external impulses as fast as I can get. Most similar was the story feature in Instagram, often also videos, although nobody every compared viewing them with Youtube.

Although Youtube also has it's scroll/impulsive it's not a direct competition. Although you could argue any form of time consumption (online) is competition.