Call me crazy, but Graham, Montana, and Brady had reasons for their success — that Unitas, Marino, Elway, Favre, and Manning did not have.
Otto Graham had Paul Brown. Joe Montana had Bill Walsh. Tom Brady has Bill Belichick. Those three head coaches were miles ahead of their competition.
Yup. Dan Marino suffered in the coaching department. While those other guys had these coaching geniuses to tutor them, Dan Marino had to make do the first ten years or so of his career by playing under Don Shula (only the winningest coach in the history of the NFL) and then playing under Jimmy Johnson (the architect of the other team to win three Super Bowls in four years).
Wow. It's a wonder Marino ever amounted to anything at all, with such deficient coaching as those two guys.