That's not competition, that's an oligopoly and they are mostly focus on their own niche for which there isn't more than a minority competitor (there's no competitor to Youtube on for non-live video, Twitch is in a monopolistic competition situation for game streaming, so is netflix on TV series, and Disney and HBO each have a monopoly on their IP).
Claiming that this is a competitive market is a joke.
I picked well-known names as examples. There are thousands and thousands of niche providers.