Not really the point - just a hypothetical. Does the game of football in and of itself have enough excitement to sustain a season as long as some of the other major sports.
I find football painfully boring if I'm not emotionally invested in the game. It's way too long and has far too many stoppages in play.
An interesting perspective.
Average duration of an NFL game = 3:05, with approximately 20 minutes of actual action. An 11% "active play to total time" ratio. If you count the huddles and returning to the line of scrimmage while the clock is running, you get 33% (60 minutes)
Basketball: 2:18, 60, 43%
Hockey: 2:21, 60, 43%
Soccer: 1:48, 90, 83%
Baseball: 2:52, ?, ?
Bordelais7: 0:30, 30, 100%
Baseball is tough to quantify; more than any other sport there is that "game within the game". And of course with many of the above, there is argument to be had about the "quality" of the action.