My CDN’s policies are pretty well set via contract. There is no provision for using too much bandwidth and I pay yearly at any rate.
I bring this up not so the average joe can host their own videos, but to point out that yes, someone can create a youtube clone. The hosting of multimedia content isn’t what stops that. A site like youtube has to attract 2 market verticals: talent and users, which is incredibly difficult without gobs of money to throw at it.