This is the key, average starting corners makes $10M a year (see Jackson, Donte). Unless they regularly gets beat deep, as every talking head will find a pff-type stat "it's a concern he was was best deep three times last season" to sound smart.
We sometimes forget these guys are first and foremost looking out for themselves. And seeing a burner on the other side of the los will make everyone back off a little, regardless of what the coach said about the deep accuracy of the QB. And the cb like just as bad 5 yards behind the receiver even if the qb overshoots him by 10 yards.