NFL fanbases are so watered down nowdays that teams don't have to win anymore for owners to make money. They feel like winners no matter what. There's very few fans left that are only all about the football. The reality is, a lot of people wouldn't even watch or keep up with the NFL if it wasn't for fantasy football.
All they have to do now is trot out 2 or 3 different uniform combinations, redesign the logos, change up the color scheme a little bit, sign one or two players nobody else wanted, and pipe in some awful music to keep fans of poorly run franchises interested. It works like a charm.