I'm guessing the Cardinals...they've been around forever and have been losers almost the entire time.

This graph really shows how horrific the Packers were in the years immediately before Lombardi. To drop 1000 points in differential in just over 10 years...playing far fewer games per season than the modern era. YUCK! Then Lombardi comes in and completely reverses that in less than a decade.

It appears the Cowboys tried to overtake the Bears in the 70s...fell just short. Then I'm guessing the Niners took the next shot with back-to-back HOF QBs...again just short. It took the next pair of back to back HOF QBs in Green Bay to finally topple those damn Bears.