Breeding kennels should be subject to tighter rules as OldMeg suggests. Id include so called "hobby" or home breeders in the inspection regime. Bitches should not be bred before the age of 2 1/2, and only two litters for each bitch before they retire from their employment.
Reputable breeders follow this kind of regime and all will provide vet certificates to confirm the parent dogs have been health checked for any possible health problems in that breed. They also provide certificates that the pups have been vet checked and had their first lot of injections.
Whichever breed is particularly popular is always overbred, health problems can become endemic because health checks on parent dogs aren't done. Bitches are bred from their first season and become weak because they live in cages, with no exercise, affection or exposure to ordinary life. Pups are removed far too young, separated and shipped out to be sold. You'll often see pups for sale on web sites, with the message it's the last pup of a litter. Prospective buyers arrive to see the pup to be told its mother can't be seen just then because eg. it's doing a pat visit to a family member who had a stroke, or some other equally emotional nonsense. Sorry for ranting but I have only lived 5 years of my life without dogs and this is a subject close to my heart.
I may as well go whole hog and say I dislike the way some people rescue dogs from abroad. I know a number of hunting type dogs who were rescued from southern or Eastern Europe. They'd been street dogs, never lived in houses and foraged for food, including killing small animals, birds etc. This behaviour is very difficult to stop once established. Being domesticated can prove stressful for these dogs who are unhappy being confined, can't be let off lead because of their hunting behaviour and tendency to just run and run.