Seems to me like people want all the top QBs to take less money for their teams whether the team made top notch investments or not.
Every organization wants to run more efficiently. The rub you seem to have is that
the idiots are running the show, why should anyone bail them out? I don't really know what to tell you. KC and Cincinnati are awfully good examples of teams doing right, personnel-wise, by their QBs. Yes, the Bengals OL has been suspect. So was KC's in that Tampa SB because they were hurt. But in general, you can't quibble with the results, notwithstanding the egregious CEH pick that really had me doubting for a minute if Brett Veach wasn't the product of lucking into Mahomes and John Dorsey's holdovers.
I also think what you get when the average fan speaks about wanting to keep QB salaries down is threefold in its outlook.
One, the average fan can't comprehend the salary to begin with. Seems unfair in a world where teachers and workers can't get paid a decent buck.
Secondly, if they can, they can't comprehend why a QB makes so much more than an inside linebacker or running back because the average fan views a team as a meritocratic concept where teammates are generally (generally) holding each other in equal regard and importance to the team. Now, the past twenty or thirty years has sort of disproven this in the NFL, but the average fan still holds basic concepts like these dear.
And thirdly, the average fan wants to win and knows that if the quarterback takes all of the pie, it's going to be harder to do so. So that's probably why you see so many people arguing for the QB to take less -- so the team and, in turn, the fan can win.