There was a TV documentary, a few years back, which showed how breeders deliberately bred, and inbred, their dogs to meet a breed standard. These practices produced the defects to which you refer, among others, and perpetuated them. Even worse, the breed standard itself sometimes demanded that the dog have a feature,such as the flattened muzzle of the bulldog, which created difficulty for the animal.
The result was that the BBC refused to broadcast Cruft's Dog Show , organised by the Kennel Club, and sponsors refused to sponsor it. This had the result that the Kennel Club announced that it would raise standards, but it is not very clear what effect their doing so has had.
The fact remains that the modern German Shepherd Dog, and the modern form of several other breeds, are markedly different from the originals, and not one of these changes has been for the better.