I think only half of this is ESPN, the other half is professional sports leagues which negotiate contracts that prevent networks from providing alternative broadcast methods. If they could, Fox/NBC/CBS Sports I am sure would not hesitate to offer streaming services to undercut ESPN (granted there is Fox Sports GO and NBC extra time for EPL, but they are more limited than their full channels). But the sports leagues they negotiate with won't allow it.

If I were ESPN, I'd ride it out. Sure you may lose compare to the old TV hegemony you had, but you'd never make it up from the streaming side while leagues have their own services.