I imagine people will say the same of gsp and anderson some day. I've been following MMA for a decade. Fedor was the greatest fighter to have ever lived up until the later 2000s. He is still the most achieved fighter, greatest heavyweight to have ever lived. This will not change if he loses 10 more fights.
what does him losing now take away what he has done in the past?
Fedor, Mir, Lytle, Serra, Hendo, Chuck, Minowaman, Maynard, Forrest, Hunt
Pickett, Cerrone, Matt Brown, Bisping, Weidman, Barnett, Lawler