Frankly, I couldn't care less if they only rendered the football field, not even the sidelines.
But most people want atmosphere and presentation, a quasi-TV broadcast type of presentation.
Don't get it, if I want something that looked like TV, I'd just watch a football game on TV.
But then, I'm not that into cutscenes either. After I view them a couple of times, I just press buttons to dismiss them and get to the playcalling screen. When you play Madden online, you don't get these replays (or any for that matter, not even the user-controlled ones from the pause menu) so no biggie.
But I would have to say that most of the gameplay action occurs on zoomed out cameras to see as much of the field as possible. In those views, you don't have to have high LOD on the players. But then you see the background, like sideline and parts of the stadium.
Still, if giving too much detail to the crowd hits the frame rate, most people would not accept that tradeoff.