I didn't trot out a random stat. It doesn't prove the opposite. 16 years. You used him as an example. That example is rare. He also got the job done. McD hasn't gotten the job done, so it isn't the same situation at all. Unless your only goal is to be a good regular season team. You want another example? Marty Schottenheimer. Coached KC for 10 years. 5-13 playoff record. Great in the regular season though (.613) Think they should have kept him longer or did that continuity not do them any good?
None of the other Bills head coaches had an elite franchise QB on the level of Kelly or Allen. You think McD would be this successful if he still had QBs like Tyrod Taylor ,Nate Peterman, and EJ Manual, or is it more likely he is a 9 game win coach at best just like the rest of them? Sure, we have had some bad coaches but QB matters and none of those other coaches had one. Continuity would have done nothing without one. Even Doug Marrone with Nate Hackett at OC went 9-7.
I asked you a question... where do you draw the line? How many years are you giving this guy to win a SB, or at least get to one? Instead of answering you just tried to puff chest like you are superior or something.
The bolded is part of my point. Part of the reason he is there so long is he has proven he can do it and he proved it early on. Twice in his first 4 seasons. McD hasn't done that and is on year 7. You say that proves the opposite? I think not.