Hart’s numbers are God awful. Why did they keep him for so long?
Remember, his contemporary Roger Staubach (163 TD, 109 Int) retired with a career passer rating of 83.4. Other contemporaries Terry Bradshaw (212 TD, 210 Int) had a career rating of 70.9, and Fran Tarkenton (342 TD, 266 Int, with all the career total records when he retired) was at 80.4.
They all played before pass blocking and defending rules were changed to goose the passing game and increase scoring in 1978. In 2002 they enacted rules to ensure QB safety. Since then, playing quarterback is an entirely different animal.
For comparison, the career quarterback rating leaders all-time are Aaron Rogers 102.9, Patrick Mahomes 102.4, Russell Wilson 100.1, Lamar Jackson 99.8, Joe Burrow 99.6 and Deshaun Watson 98.8, Drew Brees 98.7, Kirk Cousins 98.1, Dak Prescott 98,1 and Jimmy Garoppolo 98.1.
You can't really compare the QB stats of Peyton Manning, Tom Brady and Drew Brees with the stats of pre-1978 greats like Staubach, John Unitas, Bradshaw, Tarkenton and Joe Namath. The game is just so different now.