HEY is already trying to do this, but Apple changed their policy recently that if you offer a subscription you MUST allow for users to sign up through your iOS app which means paying the fee.
Also it seems to be a per case situation. They won't force Netflix or Spotify to change it, but they sure will try it on emerging apps that don't have the kind of resources those other behemoths have.
We're a place where coders share, stay up-to-date and grow their careers.
We strive for transparency and don't collect excess data.