It may be harder to monetize short video content than short text or longer videos (maybe that drives YouTube revenue nudges for longer content?).
But people like short videos, so there's a tension there. If you're in ads, maybe just buy a few short video companies, get their patents to sue their competitors, and shut them down, so no one gets access to the thing that they like but is less lucrative for you.
But maybe you're right and they would have followed an IG model just fine.