Sure, but for things like tight integration with set-top boxes / consoles / mobile devices, a thick application would be required (unless every device gets magi

Sure, but for things like tight integration with set-top boxes / consoles / mobile devices, a thick application would be required (unless every device gets magical, stable browsers with good non-desktop UXs), and if each provider creates their own media streams, you'll have enormous fragmentation of experiences and interfaces, as well as software clutter.