My first observation after much time taken to understand wtf and how that works...
Is Andy Dalton was the only veteran QB starter below tier 5. Tier 5 and above almost all have franchise QB's solidified. The ones on the line of 5, 6 seem to be your borderline starters...titans/goff/winston/rivers/ryan
Basically all those starters were able to barely achieve tier 5. If you are less than that you might be young and you might not have it. Seems to be the cutoff of decency, we are in tier 7 despite the 7th ranked D, in fact, we have the best defense tier 7 or below and its not close. The Steelers are the most similarly built team to the Bears.