Jay has the physical tools of a top 5 QB. My issues with Jay were decision making, mechanics and $54M guaranteed (3 years ago). Probably somewhere in bottom 3rd of QB pack.
Today, still has tools, improved decision making, still could improve on mechanics and today has no guaranteed money coming (favorable contract terms to bears). Probably somewhere near middle of QB pack.
So, looking at bears QB situation today, not that bad. Could it be better? Yes. Has Jay fulfilled his potential? Not yet. Can bears win with Jay? Yes, with right team around him (I.e. Denver bronco's).