There are still football fans out there. Some smart people with money to invest could start another league. I think it is over for the NFL but I don’t think it has to be over for professional football.
Heck, you don't even have to do that. Just come up with a good way to stream all the local high school football games(you would have to cover a couple of thousand games a week, but the rights fees would be extremely reasonable). Most high schools probably have some sort of video/technology class who would help you out with the production. I could easily spend the whole weekend trying to watch all the teams in my area.
And I would call it the Patriotic Football League (PFL).