Yeah, I think that's a assumption Apple made that most AppleTV devices would be in the same household where people can simply use the streaming app's ability to switch profiles. That sucks if you have roommates that pay for their own streaming subscriptions or the AppleTV device is in a common area such a dormitory. I suppose they could solve this by allowing ad-hoc profiles if AppleTV and user's IOS device is on the same network.

You must be a school or business with DUNS number and rigorous, manual verification through Apple to set up shared iPads with managed Apple IDs in the School or Business Manager Portal.