Why shouldn't content creators get to choose where they sell their content? Should Tesla be forced to sell its cars through GM and Ford dealerships so you don't have to go to more than one place to go car shopping?
Anyway, the alternative would be worse. If there was no reason to pick one streaming provider over another on the basis of content, one would quickly become a monopoly, which would be bad for both content creators and consumers.
Anyway, the alternative would be worse. If there was no reason to pick one streaming provider over another on the basis of content, one would quickly become a monopoly, which would be bad for both content creators and consumers.