Gone are the days of one head coach sticking with a team year after year... Currently, there are 17 head coaches in the NFL with two or fewer years with their current club, 11 with one year or less, and 6 brand new to their current team. The NFL has most definitely become a business with a short attention span regarding division, conference, and league championships.
There have been some very good head coaches relieved of their duties after two or three losing seasons, and team executives seem to always be in "win now" mode (except for those in perpetual "rebuilding" phases).
Lovie Smith (and Tom Coughlin) both joined their current clubs in 2004, ranking them 5th behind Andy Reid, Bill Belichick, Marvin Lewis, and Jack Del Rio as the longest-tenured head coaches in the NFL. With the exception of Marvin Lewis (how does he keep not getting fired?), Lovie Smith's stats can certainly match up well with the others, but the consistency is certainly lacking.
The McCaskey family, Bears players, and a certain portion of the fanbase all certainly support Lovie, but at what point does Lovie need to bring a Lombardi Trophy home before the team goes in a different direction? For example, would another NFC Championship loss warrant another three years? Would another North title justify another two? Or would a losing season be the final nail in the coffin?
Personally, I am a supporter of Smith, based largely on the fact that his players seem to trust him unconditionally. Chemistry and buy-in are of utmost importance, and Smith has assembled a great staff of assistants under him in the last couple years. But, there has to be a line drawn in the sand at some point, right? He's got seven years under his belt on the Bears' sideline... What will it take to make it ten?