Why is PlayStation Network a single point of failure?

The PlayStation Network is now shut down indefinitely following a security breach. I have no problem with that fact I can’t access supplementary online multiplayer gaming. But, I can’t wrap my head around why PSN has its tentacles in every downloadable application I’ve installed. Hulu, which has its own very nice authentication system, cannot be accessed now (ever again?) because I must pass my credentials through PSN. Why is this PSN layer mandatory and in front of an application that has nothing to do with PlayStation’s network? I haven’t tried but I assume the same is true for MLB.tv and the Netflix app. I’m calling it: the Apple TV is much better positioned to foster the app economy and will capture the lion’s share of the “box connected to TV” market (video, games, movies) by popularizing a much better ecosystem in the 6-8 months PlayStation spends rebuilding PSN.