It isn't quite that simple. When you subscribe to a streaming service, you don't just pay for content. You also pay for all the infrastructure and overhead for that content, including things like the development of the apps used to access that content, and so on.
With each content provider putting up their own service, we are paying that overhead for each service - effectively raising what we pay well over just the price for the content. If the content creators could instead settle on a couple of possible providers (in the model Netflix and Hulu started with), we consumers would get more content for our dollar, while the content creators would still get paid at the same rate for the content.