Counter examples to some points made here:
Lawrence Simmons (
https://cust10.myfootballnow.com/player/496): Signed in 2021, 119.77 rating in 2021 preseason, 104.05 rating in 2021 season with 6012 yards passing, 62 TDs to 27 INT on a 61.4% completion percentage,
so play knowledge is probably not as important.. 79 arm strength, 84 passing release, 77 accuracy, 82 look off defense, 84 FOV, 52 scrambling skill, 95 intelligence. 82 overall by my weights.
Dennis Sommers (
https://mfn23.myfootballnow.com/player/2607): 102.51 career rating, 62% completion percentage, 138 TD to 56 INT in 5 seasons. Just 62 in passing release, 58 intelligence, 7 scrambling skill, 58 intelligence, and 69 in arm strength. Balanced by 99 FOV and 100 accuracy, 85 look off defense.
Looks like FOV, accuracy, and look off defense were more important than intelligence, passing release, scrambling skill, and arm strength intelligence. 74 overall on player page.
James Mitchell (
https://cust21.myfootballnow.com/player/494): 111.66 passer rating in first season with new team, 4370 yards passing, 41 TD to 14 INT,
so play knowledge is probably not as important. 100 pass accuracy, 96 FOV, 77 look off defense, 79 passing release, 71 intelligence, but
just 61 arm strength. Currently 79 overall on player page.
tl;dr - I could list other examples but basically I believe a QB only needs to be above average in a large combination of the attributes I listed for the above examples. No one trait is a make or break. On my teams quarterbacks with average attributes can perform sufficiently well in the regular season but have been unable to win me any championships (and are more prone to worse performances against good defenses in the playoffs), which is why I still value above average to lower elite quarterbacks. Quarterbacks certainly are not a premium but you can't gloss over them either.
What sets above average quarterbacks (in terms of rating) apart from other above average quarterbacks is the scheme and quality of players around him. In other words, you can build a team around a quarterback and game plan to make him play better than his apparent rating, but in crunch time a very good quarterback with a proper team/good game planning will outperform mediocre quarterbacks in the same situation.