This is truly one of my few pet peeves.
I have raised and shown and breed English Bulls for over 30 years and have many Champions bred by over the years(Now Retired from ring)
The reason the Designer dogs took off and soooo many people fell for it is because AKC finally cracked down on breeders only allowed to have so many litters a year , if you would go over the limit American Kennel Club could keep you from reg. anymore unless you let them into your kennel to see your breeders and check out you out.Make sure yoour paper work is up to Par and many other important factors.
Now the backyard breeders making a living out of selling purebred dogs had to figure out a way to live off of selling AKC puppy mills FIGURED it out breed mutts and call them designer breeds, AKC can't touch them and the general public fell for it!