Not sure where you're getting the data, 2009 total earnings as per bloodhorse is $4,551,974 (CZ) versus $4,539,456 (Fupeg).
http://www.bloodhorse.com/horse-raci...-lists/general
On a cumulative basis (lifetime as a stallion): CZ has 344 foals, 256 starters, 196 winners, of which 184 were 2yo starters and 99 won as a 2yo;
FuPeg has 1086 foals, 560 starters, 323 winners, of which 311 were 2yo starters and 98 won as a 2yo.
In 2009: CZ has 171 runners, 100 winners, 41 repeat winners, 6 stakes winners of 14 stakes and 1 graded stake winner (Get Serious-G3 Red Bank.)
FuPeg has 308 runners, 118 winners, 54 repeat winners, 5 stakes winners of 8 stakes and 2 graded stakes winners... both not in the US/Canada/Europe (Vistoso-Mex G1 Derby Mexicano, Cats Whisker-Aus G2 Jayco Blazer S.)
I think it's undeniable that City Zip is just plain better than FuPeg and he stands for a third the price.