When you move to looking at data as a public asset, you change the philosophy completely around how organizations view, control, and manage that asset. At the moment, in most large organizations the individual who controls the database has power and tends to control a lot of decision-making. It's very hard, culturally, to change that philosophy.
Private organizations would look at data as an enterprise asset, as enterprise-wide information that could be shared and leveraged for decision-making. Most government organizations are not at that point, but this really offers an opportunity to almost leapfrog that whole cultural transformation. Rather than having to work program by program to get individual program areas to free up information, once you've taken a specific policy position or stated a principle, the releasing of that information to the public will enable governments to cooperate better internally.