You don't need a team's playbook to understand route concepts and how they are designed to counter a defense. Man , Cover 3 , Cover 4 , Cover 2 and 0,1 are all countered by specific concepts like flood, mesh, sticks, screens, etc.
You have clear outs by design to move safeties, you have out routes to hold cover 3 corners (See Dante Jackson blownn coverage against Seahawks), you have underneath routes to bring down the linebackers to free the medium mid.
Just because you don't understand this stuff.. doesnt mean its crap.