506Sports.com, which provides regionalization maps for network NFL games, also lists the local home market stations broadcasting any games that are on Prime Video, Netflix, or exclusive to ESPN or NFL Network.I believe the NFL is required to air its games in the two teams' local markets via broadcast TV. For example, tonight's Amazon Prime game between the Seahawks and the Bears will air on the Fox stations in Seattle (KCPQ/13) and Chicago (WFLD/32). They came up with the best offer for each city, but any Seattle and Chicago station could have bid on the game if they wanted to.
The NFL puts those cable/streaming games up for bid for OTA stations in the teams’ home markets. I suppose it is theoretically possible no one would bid on them, but that will never happen in reality.