Is Curlin being overrated by the margins over nothing horses?

One horse that both Curlin and SS ran against was the closer Delightful Kiss. In both races, Curlin and SS fired their "A" game or at least close to it and DK seems to be a pretty reliable decent horse.

In the TB derby, DK lost by 6 1/4 lengths, although he ducked out quite a bit at the start, in Ark Dby, he lost by 11 1/2 lengths.

Perhaps more interesting, in the stretch runs of each race, he lost 2 3/4 lengths or so to Curlin, and he lost about 1 1/4 lengths to SS. The Tb Dby was 1/16 of a mile shorter and probably wind aided in the home stretch but one would guess that based on this, Curlin is certainly not overrated.