YES, they do.
I kjnow perfectly healthy dogs that were CERFed... turned out they had cataracts. Dogs were spayed/neutered. Not bred.
In my breed, a doberman can appear perfectly healthy, but be vWD affected. Then an idiot can breed that dog to another "perfectly healthy" dog, that also happens to be vWD affected. They produce a whole litter of vWD affected puppies. And half of them end up being clinical.
What would you tell those puppy owners, as they watch their puppies bleed to death from a simple scratch? Oh golly gee whiz, the parents were perfectly healthy!
Dogs with poor hips may never show signs of it... but they can pass it on, especially if bred to another dog with bad hips. Same thing with elbows.
Responsible breeders do extensive health testing, because they feel that EVERY dog they produce should have the very best start in life. They love their breed, and want to improve their dogs by reducing health problems, increasing longevity, improving structure and perfecting the correct temperament.