I think there's a big delta between having experience with operating those services and trying to launch a service that on its first day had 10 million users and its expected to be at 100 million users in 4 years.
ESPN and MLB TV are probably pretty far from those numbers.
But just as a controlling shareholder. I don't think they have any input or say on Hulu's operation besides the typical influence you can exert as a board member even when it's from a vote controlling position. I may be wrong but I doubt they can use Hulu's streaming technology or IP in general unless they license it from Hulu somehow. If Hulu was an actual Disney subsidiary it would be different. Although Hulu is controlled by Disney, Comcast still owns a third part of it.
Disney is the the biggest kid at the pool in media and their is really nowhere in the entire entertainment industry where their influence can't be felt. Disney happens to 100% own hulu now, but even before that I don' see how you can look at their operations and not conclude they were in control.
Disney also owns ESPN and their streaming platform.
So between Hulu, ESPN, and Bamtech they definitely aren't new.