why the fuck can't I just have one god damn app that can load ALL of my
  shows/movies/livetv and takes care of payment to whichever company is providing the content

Which is what Apple have tried to do with the TV app [1]. Except it doesn't include Netflix. Or Amazon [2]. And I'm sure there are plenty of others. Walled gardens eh?

[1] http://www.apple.com/newsroom/2016/10/apple-unveils-new-tv-a...

[2] http://bgr.com/2016/11/17/apple-tv-universal-app/