I actually had a thread about this topic on CCS...on a sidenote, not only was I banned from CCS, but my entire account and all of my old postings were physically removed from the site permanently. Can you imagine that? Treating a sports discussion forum as if it were the USSR Politburo? It's crazy.
Anyways, I found only 3 QBs in NFL history who were comparable to Cutler in tenure length with one team and mediocrity. Lynn Dickey of the Packers was the definition of a hot-and-cold QB, Jay Fielder of the Dolphins who would usually 'lead' his team to the postseason, and Mike Pagel of the Colts who would end up playing every year due to bad drafts and injuries to other QBs.
The normal pattern is if a mediocre QB has a long career, he will bounce around from team to team as kind of a 'stopgap' guy (like Ryan Fitzpatrick) but never staying with one team, or he will stay with one team and will alternate great seasons and below average seasons. What is unique about Cutler is that he had such a long tenure with the Bears and never had a 'teasing' great season...it was just year-after-year of average and poor seasons. Again, couple this uniqueness with the fact that Cliff Stein made Jay Cutler the highest paid player in the NFL, and it's beyond comprehension.