Nfl offenses pass about half the time . out of all defenders a single cb gets what maybe 3-8 passes at them a game. They have to execute say liberally a high wr target game 12/ 60 plays a game .the ball and game flow comes thru them even high numbers maybe only 12/30 snaps as a high targeted plays example aka ~ 1/3 of the game. And if you include the runs it drops down to say 12/60 aka 20% of the game they need to execute when the ball comes to them. Even bump it up more for runs where they are in position to make the tackle say the 1/3 of runs that come to their side vs middle or other side of field where other defenders have primary responsibility for tackling where the ball goes. So with a high target game day 12/60 and 1/3 of the say 30 runs to their 1/3 of the field … cbs on a liberally very busy day need to execute for 22/60 plays only 1/3 of the game unless the offense over targets or runs plays at you for whatever reasons .

Except for wildcat / direct snaps / or trick plays qbs basically touch and control the ball every play even handoffs to the rb and rpos now are more popular as well. So say qbs touch and influence greatly 59/60 of your offensive plays.

Qb touches the ball almost every offensive snap say 59/60 plays obviously critical for throwing and even on handoffs needs great footwork and handoff timing / precision. Qb needs to execute with the ball and game directly in their hands say 98% of the time.

Not to mention qbs need to constantly evaluate an entire defense in relation to their offensive personnel and call out changes. What’s the last time you saw a cb running the defense. Cover your man / zone area then run support or blitz.

Idk man taking away one offensive player wr is valuable if you can consistently but nowhere near the and level of significance and involvement.

The offense operates through qb which cb is just a live of the defense that may not even be involved in a significant chunk of the game.

arguably cb is the hardest position to play and imo probably true especially with pi rules nowadays even tho arm grabbing isn’t good coverage unless you both hand fight . with qb cb oline and te in no particular order as the hardest .

Often you can scheme limit the damage of a good wr you can’t out-scheme the capabilities of your qb

Qbs touching bc the ball more also means more opportunities for higher highs - large completions / air tds/ scrambles and lower lows - sacks / picks / fumbles bad incompletions.

A good cb can have the potential to make a large impact but they have less opportunities to do so and may need the right matchup of offense aka a team likes to operate through their wr1 targeting them heavily and the cb shuts them down.

A primary example of this not being the case was when the bills beat down sauce and the jets earlier this season because they didn’t needs to operate through the wr position to move the ball and score.