A game takes roughly 3:30 hours, and you generally get 3 plays a minute of game time which take about 8 seconds each. It's a safe bet that less than 30 minutes of the 3-4 hours you're in the stadium is actual ball in play situations. There's maybe another hour of noise making during huddles or pre-snap.

I can stay fully engaged for an hour and a half and still have plenty of time take advantage of the wifi in the stadium during timeouts and stoppages. American sports are purpose built to give people the opportunity to spend money elsewhere in the stadium during the game.

It would've been awesome to check other scores, plan post-game events, order food, check the traffic, send text messages, etc at games when I attended. Half the time I left was because I needed to contact someone and couldn't.