What you are saying is absolutely true and it should be the case that you go to a registered breeder to get a healthy dog. Sadly this is not the case. It wasn't for us when we went to get our French Bulldog.
We're from the UK and we went through the kennel club to seek out what they themselves recommended as a "reputable breeder". After finding one with an available litter, we went to meet our puppy. We saw the health certificates and a vets report and paid a deposit on him - total price £2000 pounds. We were more than happy to pay such a high price because it's not wrong to assume that what you're getting is a healthy dog for such an amount right? Wrong! Our puppy came to us and was great for the first couple of weeks but afterwards I noticed that he started to sit with his back legs totally spread out in the splits position. I contacted the breeder and she said "completely normal, nothing to worry about" my husband and I weren't convinced. An x-ray at the vets then uncovered that he had a hemivertebrae defect in six of his discs. We contacted the breeder but she refused to give a refund or to acknowledge that this dog was ill, saying that we were just trying to threaten her reputation to get our money back, even when our vet sent her a letter. "Fine" we thought the Kennel Club will want to hear about this especially as this is a genetic defect and she was planning to continue breeding from her dogs. Unfortunately they were no help either. They said that French Bulldog breeders already had a bad name and they refused to take this breeders name of their register! She is registered on there still and this was 2 years ago. Unfortunately for our puppy Marmite, 9 weeks after we discovered his disability and 12 hours before he was due for surgery, he had massive fit and had to be put to sleep.
To top it off, about 9 months ago there was a documentary shown here on the BBC that uncovered the despicable practices of registered breeders and totally trashed the reputation of the British Kennel Club because there were all these terrible things going on that they knew about and had even recommended! As a result of that the Crufts dogshow was not aired on television.
So my opinion of these "registered breeders" is not good at all and not just because what happened to me. My sister also had a terrible time with a registered breeder but then there was this documentary that just blew the lid off it all... It's probably different in America but this documentary was totally shocking and interesting! It's a shame really because there are genuine breeders out there that do have the dogs / breed interest at heart and it's not about the money, we just weren't able to find them!
After all that we now have a Jack Russel mix.