Wild NFL Rushing Yardage Stat
Also the days of the QB bouncing around in the pocket 5 seconds or more waiting for the deeper routes to develop is a rarity.
Now it's quite common for the QB to get the ball out in less than 3 seconds, getting the ball to receivers in shorter patterns
Then consider the athletic front 7 with their speed and quickness in today's game.
Add to that the many blitz packages involving DBs that don't allow plays to develop downfield.
Then there's the changing of the guard through age attrition of the great ones that haven't been equally replaced.