So, all QB's are expected to complete all of their passes, every time? Even if.....a receiver runs the wrong route, the wrong speed or without proper timing, while the O-Line allows free runners? Like Rogers, Brady, Raperberger, Brees, et. al. ALWAYS do? BS. If all 11 players execute like they are supposed to, maybe they get close to perfection, but in the first game of the season after limited playing snaps in preseason? Playing QB in the NFL isn't all that easy and blame is often placed on them as they are often the lazy analyst's scapegoat for most failures/losses.
In Baseball, Ted Williams IMO was the greatest hitter of all time and yet his best season was .409, or approximately 4 hits out of every 10 tries. NFL QB's have different #'s to attain success, but none have been, or ever will be, always perfect every time they step on the field.