Why did this happen? Quite simply, attitude. Because they really didn't believe they could win, even though each team dominated those games until the very end. (And, on the flip side, the Pats and Chargers ultimately won because they believed they would win -- and they made it happen.)
This "never say die" and "we will make it happen and win" attitude applies equally to any organization (including companies small and large). I have seen it time and time again.
Attitude is a central ingredient of success in all things -- including business. In fact, I agree with Seth Godin that attitude is THE most important ingredient for success. His blog in this regard is worthy of a read.