A supposed wise saying in racehorse breeding is "breed the best to the best and hope for the best".
It means send an expensive mare to an expensive stallion.
My understanding of it is you are encouraged to buy an expensive mare, send her to an expensive stallion, wait a year for the foal.
The winners here are the seller of the mare and the stallion owner.
The offspring of these matings are often useless.
You will only find out if the horse is any good three years after the mating.