You're absolutely right with the advertising aspect. YouTube is not simply a video hosting platform. It is also an advertising platform.
YouTube's dominance is not because video is impossible to host but because YouTube takes care of the advertising/revenue aspect for content creators. Any competitor would need to provide a similar service, and that's hard to do at the same level when you're not run by the world's largest advertising company. A serious alternative to YouTube would need to draw creators like YouTube does, and you need some sort of built-in way to (probably economically) incentivize them to create videos and put them on your platform.
Or like
https://watchnebula.com/
be owned by creators in the first place and try to finance by subscriptions without ads. But this obviously will not scale like Youtube..
I followed your link, then struggled to find something as you have to choose from a list of thumbnails. I then clicked to view something and immediately hit a paywall.
How are you supposed to "discover" this content? That is where youtube is so strong. Often on youtube I will be directed to patreon, etc - does this work on the same principle?
A lot of large YouTubers (like Wendover Productions/Half as Interesting) have been doing sponsored ads for a thing called 'CuriosityStream' which is basically Netflix for Documentaries/Non-Fiction and as part of a bundle if you subscribe with their link you get Nebula for free as an extra for as long as you pay for CS.
It's mainly existing content from YouTubers but with premium exclusive videos like Patreon has.
YouTube's dominance is not because video is impossible to host but because YouTube takes care of the advertising/revenue aspect for content creators. Any competitor would need to provide a similar service, and that's hard to do at the same level when you're not run by the world's largest advertising company. A serious alternative to YouTube would need to draw creators like YouTube does, and you need some sort of built-in way to (probably economically) incentivize them to create videos and put them on your platform.