If I recall correctly, this is more due to Netflix than Apple. Not sure if it is business terms or data privacy, but Apple seems open to as many TV App participants as possible.
It's the other way around – Apple imposes certain demands on content owners to appear in the app, one of which is basically treating them as dumb content pipes under Apple's brand – so Netflix, IMO wisely, said no. https://9to5mac.com/2019/03/18/netflix-apple-video-service-t...