Any given play generally takes 10-20 seconds, and you're going to be running, bare minimum, 2 plays per 8 points(1 for touchdown, 1 for 2 point conversion). So that's about 25 seconds per score.

If the teams are remotely well matched(i.e. aren't a Breaking Madden team), they'll take at least 2-3 minutes per possession, since you're most likely going to have 4 downs, which have a play clock of 40 seconds(most teams use around 30/play), so the "average" shortest possession is something like 2 minutes.

The point of all this? The Breaking Madden games are really an outlier that you'd have to specifically code for.

The answer from EA's point of view is that people buy it every year, so of course they'll make a new one.

The explanation from the user's point of view is that much of the magic of the game comes from it reflecting the teams, players, and plays of the actual NFL. When some quarterback gets traded to another team, you want to get next year's Madden so he's on the right team in the game too.

This is one of the really cool things about the game. There are millions of people who have detailed knowledge of different teams and players and what their strengths and weaknesses are. Madden lets you take that otherwise pointless barroom trivia and use it to actually be better at the game.