From Sunday Ticket Trial: ESPN Proposed 70.00 Full Season Package

The NFL doesn’t want cheap access to all games because they still make billions on network contracts - though I still believe that they are aiming to eventually move to a “pay per view” streaming structure at some point in the distant future.

The teams also still need people to go to games to pump up the profits of the team owners.
I think it has more to do with FOX/CBS protecting their noon and 3pm windows.