Keep in mind that all of these products in many cases compete with other companies (music -> spotify, apple, ytr -> netflix/hulu originals, kinda, YTL -> twitch, YTTV -> cable providers). I, as a consumer, wouldn't want these things to all be bundled. I use spotify for my music, and I don't want to have to pay for Play Music or youtube red unless I use those services.
I can't even imagine how some kind of "unified google media" thing would work.