First of all, we would NEVER geld a weaner or even yearling. We like our colts to get a nice neck on them, and mature a bit before gelding them, it does make a difference in their appearance, and anyone with a good eye can see it. They look better, and we're a position to wait.
Secondly, We have some bloodlines we're pretty proud of, both in saddle horses and our bucking stock. One of the colts I speak of is a double-bred Dash For Cash, and Special Effort 3 yr old. We have lots of people interested in this colt. As for the other colts, since this is a horse riding forum, some people may not be familiar with bucking stock, but NFR level horses are quite valuable. We have a few out of a mare that sold for $125K last year at the NFR sale. These aren't carrot eating pets, they are top quality bucking stock, which is why we wait for the cream to rise to the top. Once we know what we've got as far as the colt's ability and value, we decide what to do with them.
Another reason, we had a 2 1/2 yr old that still hadn't dropped a nut.