I get that, I really do. And you are right, many disorders in dogs is subjective, such as hip dysplasia, even with OFA and Penhipp. But in my circumstance, working with Collies, the primary breed disorders, CEA (collie eye anomalies) and MDS (multi-drug sensitivity) BOTH have DNA tests to establish dogs as affected, as well as their carrier status. All my my dogs are normal-eyed.non carriers of CEA and they have all been tested as not having the mutated mrd1 gene responsible for MDS. But this is something most collie breeders do not do. The DNA tests are out there - they are admitedly more expensive then the one you mentioned ($180 each for the CEA test if testing multiple dogs, $75 for the mdr1 test). But many collie breeders do not test, and those that do will continue to show and breed afflicted and carrier dogs, because it is believed that 85% of the breed are carriers and it is particularly prevelent along show bloodlines.
I actually have another related question. (again, sorry for so many questions!) How often are horse breed standards edited and changed over the years? It's common in dogs for the parent club to elect to rewrite the entire breed standard to include or reflect current showing trends - which is why Collies have gotten bigger, Boston Terriers have gotten smaller, and show ring GSDs are almost unrecognizable. Does this happen a lot in the horse world?