Opposing QBs seem so good because the bills defense is so lousy. Then Fitz looks so lousy because he practices against a lousy d, and plays against such better defenses. Thus, Fitz needs to play vs. the Bills d and he would look amazing!
9 games in, these QBs have worse QBR than Fritz... But yet almost every QB on this list is thought to be better especially after observed playing aging the bills d.... Remember Sanchez lookin like Dan Marino in the opener. He is bottom 5 in QBR.
Kelly Holcomb and John Elway have almost identical career QB ratings. Clearly, Holcomb was not nearly as good a QB as Elway. But Holcomb focused on short, high percentage throws; whereas Elway gravitated toward longer, lower percentage/higher reward opportunities. QB rating takes completion percentage into account; which means that it unfairly rewards QBs in the Holcomb/Trent Edwards/Ryan Fitzpatrick mold, and unfairly punishes QBs like Elway.
John Elway has a significantly higher career yards per attempt stat than Kelly Holcomb; correctly indicating that Elway was the better QB.
This season, Ryan Fitzpatrick is averaging 6.8 yards per pass attempt. Eli Manning and Andrew Luck are each averaging 7.3 yards per attempt on the season--consistent with the observation that both QBs are playing at a much higher level than Fitz. Cutler is averaging 7.1 yards per attempt; Stafford 7.0 yards per attempt. Tannehill is averaging 7.1 yards per attempt--not bad for a rookie! His season average should go up a little on Thursday.
On the other hand, some of the guys on your list have lower average yards per attempt stats than Fitz. Weeden, for example, is averaging just 6.2 yards per attempt.
Some of the QBs you mentioned are playing significantly better football than Fitz, some are playing slightly better than him; and a number of those QBs--such as Sanchez--are below average players; and are not playing at the same level as Fitz.