This isn't football school. If you are fan of the game of football you probably have an understanding of blocking schemes and how recievers run their routes. Football is an exciting sport with drama,skill, strategery, and every NFL game means something to the team. NFL football is an event, not one of 82 games or 180 or whatever baseball plays.
If a person grew up playing football they know the jobs of each position, now the anouncer needs to anounce whats happening, not show us how informed he is about the game. As a fans knowledge of the game grows you start noticing and appreciating the DE and the Tackle having that brutal battle or the 80 yard drive all on the ground.
No, most fans don't understand that stuff, and they don't care. And the reason football is so successful is that it's a perfectly enjoyable game without understanding that stuff.
Most of the fans of popular sports don't grow up playing the sport. This can be seen just by how the female demographic numbers have been climbing lately, this is especially true in football which is having it's audience grow across the board.
As a fans knowledge of the game grows they start appreciating the little things, but notice the coverage is still geared largely to people that have no knowledge of the game, and the coverage doesn't do much of anything to help you learn the game.
You can tell what the average fan of a sport is interested in by watching one regular season game and paying attention to what the color commentator talks about (playoffs get an audience of people that watch very little of the sport so coverage gets dumbed down, so it's not a good judging tool). That color commentator is geared towards the average fan, he's supposed to talk about stuff the average fan probably didn't notice but actually cares about. We know from how the game is filmed that the average fan didn't notice how the receiver ran his route, he wasn't on camera during the play until the ball got to him so they couldn't possibly have noticed, and yet they don't talk about it. That tells you everything you need to know, the average football fan doesn't care what the receiver did to get some room from the corner so he could make the catch. Now in soccer and hockey that same kind of movement and trickery is the heart of the coverage, it's always talked about, anytime there's a good scoring chance. In all three sports it's a very subtle thing, involving head bobs, shoulder fakes, and occasional taps on the defender to try to make him think you're going in a direction you're not. One group of fans is interested in that, one isn't. Neither is better than the other, they simply are what they are.