I have so many thoughts on that
. There are a lot of well-intentioned breeders out there that are destroying breeds by trying to get a specific "look" for the dogs. This is particularly common in German Shepherds as well as in the breeds you mentioned. Many people breed for a slope without actually paying attention to research that shows how detrimental an extreme slope can be to a dogs' gait and development. There are GSD breeders who breed dogs with FANTASTIC temperaments that are nearly crippled because of their slopes, or dogs that are hindered by the slope. They genuinely believe nothing is wrong with this because it's so common now in the dog shows that it's just widely accepted.
I know for GSDs the UKC recently put in some stricter breed standards to be more specific in an effort to prevent these extreme slopes from continuing. I think it's really sad unfortunate and I do not want to support or endorse those breeders in any way.
Many people, unfortunately, who are new to purebreds might purchase a dog from one of those breeders thinking everything is great because the parents are conformation champions or fit the "look" and "temperament" and that furthers the whole fad. Education is important here so people know what to look for when evaluating a breeder.