Because it sure as hell is not the opportunity costs of having their content on their own streaming service. Like Toy Story 4 released months ago, did a billion in cinema, but they still won't have it on Disney+ until.. somewhere in 2020. Their version of "betting the company" is "all the stuff you used to have on Netflix, but now you are paying extra".
Streaming Video is incredibly fragmented. It's honestly frustrating. I don't want to subscribe to 5 services. I currently have Hulu+Live, and it has ESPN, and lots of other channels I like, but doesn't have the local Fox station, or the local ABC station (only the national fox news and abc news).
Excessive Fragmentation is going to cause everyone to go back to pirating stuff, like they did before Netflix made it too cheap and easy to bother.
They are all playing to kill Netflix and other competition so they can establish monopoly like they had on cable.