No. 6: The 2015 exodus
On the surface, players retiring or leaving might seem a bit extreme to put on No. 6 of the top moments of the decade. Players do that all the time.
However, this was the moment the 49ers truly had to rebuild. The Super Bowl-caliber team was gone, and it had to be rebuilt.
Defensive end Justin Smith called it a career, while linebackers Chris Borland and Patrick Willis would announce shock retirements, while seemingly poised to be big parts of the defense. Offensive tackle Anthony Davis would retire (for the first time) also.
It’s only been this season, the 49ers have managed to recover from these departures.