> Of much greater concern is that the vast majority of videos on the internet are on youtube

Nope. Youtube host currently around 6B videos (adds around 1.2B a year). Facebook is currently around 3.5B, Instagram around the same, Twitter around 2.5B, Tiktok close to 1B etc. The general internet is around 26B videos and counting.

What makes Youtube important is the fact that most users think of it as a search engine. You can always find it on YouTube, while it's "impossible" to search for videos on Twitter or Facebook.