Well, think about what you just said, look at the time frames you're talking about when Madden was promoting a game closer in simulation. They had one keep element pushing them to make a credible game, COMPETITION. EA couldn't just cruise along with Madden back then because there were other companies that created football games before this exclusive monopoly destroyed the core of sports gaming. Madden has ZERO motivation to make a game that sim fans want. There's nothing out there to measure themselves by except old titles which sadly are still be compared to Madden. Kinda shows you how far they actually haven't come.
This is why Madden will never be a sim. They are catering to exactly what you said, the casual gamer who knows nothing about football and could care less to know. Most people don't want to play a sim because that requires thinking and strategy. That is too time consuming and considered boring to the average Madden player. And those ore the people EA cares about the most because they are Madden's biggest supporters.
Also, lets not get confused about the numbers. Madden sells are misleading. True enough you have a loyal fan following of casual players but the sim crowd also buys Madden because there's no other alternative. But again, they will never cater to the minority, only the majority, which is the casual gamer.