What is the problem of sites hosting their own videos?
So I don't know the answer to our question either but according to them we're overlooking something
The client-side player isn't an out-of-the-box thing, either-- solutions like Video.js and MediaElement.js need a myriad of plugins to approach the YouTube player's functionality, and default browser players get nowhere close. But it's the smaller part of the story, imo, because at least it's just JavaScript & CSS to deliver.