Netflix has a far smaller catalogue and can cache content in exchanges very close to the user, see [1]. Also YouTube pays their creators.

[1]: https://en.wikipedia.org/wiki/Open_Connect

Google has its Global Cache: https://en.wikipedia.org/wiki/Google_Global_Cache

One might imagine that the cache-ability is lower than Netflix, I can't comment on this, but GGC is very significant.

Netflix is a production studio with an app, Youtube is a hosting service.

500 hours of video getting uploaded a min plus processing costs (including AI) for no upfront $$s. Far simpler CDN optimization

Fewer unique video hours, YouTube pays residuals, vastly smaller library to personalize