From a consumer standpoint, life was much better when that was the case. One app, one service, pretty much anything I want to watch. Per-network streaming services were just a glint in some executive's eye, and things were good.
The current state of things is confusing, expensive, and user hostile.
I was trying to figure out how to watch Rick & Morty S6 the other night. It'll be on Hulu, but not for months. It'll be on HBO Max, too, but it's only downloadable for offline viewing on Hulu. Wanna watch it now? Need a cable subscription, even though Adult Swim's website says "now available on HBO Max".
I like the idea of any streaming service being able to license any show, if they can pay the fee. Another comment mentioned the Paramount Decree as a similar example.