In an ideal world, each streaming service would provide the service itself, users can pick whichever app they like, and connect that app to the services they use.
In the real world, each company wants to be THE number one streaming platform, and wants users to use their app above all else. So each company reinvents the same things, and users need to deal with the mess of N apps for N services.
The idea of cooperation is completely alien in big tech companies. Descentralisation is perceived as dangerous, since it doesn’t let each individual be the number one.
In the end, because everyone want to be the number one and screw the rest, they all end up sucking. This is obviously predictable, but management everywhere remains oblivious of it.