The difference in the European registeries is that the stallions need to be performance tested, and the mares need to have that quality of sire for a minimum of five generations.
Only sons of Main Mare Book mares can be considered as stallion candidates.
The development of the indexes is another tool to help breeders capitalize on what a stallion can contribute or minimize what you don’t want to appear.
The KWPN system is extremely ruthless in culling stallions they approved through rigorous testing, but if the foals don’t pass muster, the stallion is put on a watch list and can lose his license. If a stallion is not heavily marketed or doesn’t belong to someone with a sizeable mare band, that stallion may not have enough get to be evaluated, even tho he is quality.
The jury not only looks at foals, but then again at intervals and a sufficent number of get need to be competing successfully.
They look for every reason to thin the ranks of the stallion roster so that only the best are used for breeding.
Stallions are also screened for OCD and semen quality.
I don’t know if QH and Arabians and other breeds common in the US have to go through such a grueling selection process, but I think if the boy has testicles that is enough for some owners to make him available as a stud.
I think that the mares and stallions who have gone through this very demanding screening process can and do produce foals that easily go for $10K and above. The process is taking a lot of the guesswork out of the equation.
Those of us who have been around the block a few times know that not every mating produces a foal better than its parents. No one here is saying that every WB foal should be started at a $10K price. There are too many variables, including the cost to produce said foal. Someone with plentiful pasture has a lower overhead than me, on the edge of the desert, with a bale of alfalfa costing $13-14.