To continue on the Risky Business Ruby Thread.
When you look at the basics it becomes clear that breeding is a risk-reward relationshhip. Breeding dogs like Corky (known dysplastic) the reward was a top performing dog while the risk was a dysplastic dog. The number of Corky offspring becoming top performers made the rewards worth the risks.
As time progressed breeders became aware that OFA and other tests could reduce the risks of producing dysplastic dogs. However, total removal is not the rule but the generally approved practice. Occasionally a top performing individual is identified that carries a genetic defect. Removing these individuals from the breeding population might have an adverse effect of the overall population.
I advocate testing the breeding population, but not total removal of these animals. Each breeder must measure the risks, but for most there are dogs in the population that don't carry the risks.