This isn't the point OP was making, but I don't think Amazon counts. Not because "everyone has prime", but because you can pay them extra money to add content to their platform. For example, you can pay to add British content, CBS, or HBO. Amazon is doing streaming right.
I don’t think that’s a good reason. HBO will likely not be an add-on in near future. Hulu allows you to add Showtime too.
CBS or Showtime have a good chance of not remaining with both products. Once CBS merges with Viacom [again]. Showtime and CBS’s new parent company will have to decide what to do about their streaming future.
Edit: Hulu has add-one for HBO, Showtime, Cinemax, and Starz. Hulu obviously counts so then Amazon should count too.
