Drew Brees has been putting up inflated numbers in a pass-oriented NFL these days.
Dan Marino was passing for 4,000+ yards at a time when a QB with a 3,000-yard passing season was considered an All-Pro candidate.
P.S. -- This is what makes Joe Namath's 1967 season perhaps the greatest ever for a QB. He passed for over 4,000 yards in a season when only two other NFL quarterbacks even passed for 3,000 ... and he was 700 yards ahead of the #2 QB.