[Nunyerbiz]

The amount of scoring doesn't really significantly shift. Over the last 30-35 years, a bad offensive year might see NFL teams average 19.5 ppg... while a high scoring year might see 22.5 ppg. It's not like scoring was significantly lower 30 years ago, but they tended to score more on the ground and less in the air... In baseball terms, similar amounts of runs scored but with more singles / doubles and less home runs. I think fans sort of subconsciously associate conventional rushing based offense with good defense... even if the scoring numbers don't fully support that conclusion.