They went from SB contenders to the bottom of their division in one season. Didn't see it coming either.
They probably didn't either.
A lot of things have to go right to make it to the championship, and then win it. The statistics show that most teams experience some kind of dropoff after SB seasons.
The oft-cited "window of opportunity" is limited, and in the salary cap era where depth is limited, injuries to the starters can drastically alter the trajectory of the team. Going deep into the playoffs means extra wear and tear on bodies, on top of normal aging. Big signings like Bosa and Deebo not playing up to their contracts doesn't help. Bringing in a free agent who doesn't fit into the culture of the team, like Campbell, another hit.
Whatever voodoo/alchemy the Chiefs are practicing is a secret, but the part that is known is the stability in their coaching staff, which has remained relatively intact long term. Bienemy left (and has kinda followed the same kind of trajectory the Pats assistant have) but Reid is still in charge, and has a stable group that has remained loyal.
As good as Shanahan is, he's yet to show he can get over the hump, and makes some puzzling decisions at times. His system certainly seems to chew up RBs. The team has cycled through multiple DCs, and has lost front office personnel to others.
Lastly, whether one believes in the curse or not, McCaffrey was most recently featured on the cover of Madden, and has missed most of the season.
That said, they're still starting from a better spot from which to reload or rebuild. The Rams are showing that with the right moves, it can be done relatively quickly.
The fans in NY, or
Oakland Las Vegas probably wish to have the same problems, or expectations. Sorry Pach…