I dont think the expectation is for a big run up in tv prices. The NFL demographic is aging rapidly. Ratings are fairly flat overall. Ratings are down in the younger demographics compared to 5 or 10 years ago. None of these supports a huge price increase in tv payments (maybe this is trumped by Amazon and Netflix trying to expand by having a bigger NFL slice)
I suspect the speculative dream right now is international franchising. Each of the 32 owners is excited get their share of the 2+ billion dollar franchise fee each for London, Berlin, Madrid, Rome, Tokyo and Beijing someday. Followed by a surge in media values. I am not sure it happens, but I think that is viewed as a big upside for the NFL, and one reason a couple teams have to schlep over to London and down to Mexico City every year.