My dobie lived till 13 on dog chow. But you look at pics now of what I thought was a healthy dog then, and he just wasn't. His fur had no shine to it. The color was dull. His teeth were horrible (I remember him going under a few times for cleanings). And at 6 years old, he had nowhere near the energy and fitness that Jemma and Boo have.
There also probably weren't puppymills pumping out most of the pets back then either. I have no doubt that some of the dogs I meet who I know come from mills aren't healthy because of their breeding.
Do you think Jemma's breeder cared about genetics? Heck no! Do you think they cared period? Heck no! But my dobie came from one of the best breeders in Quebec at the time.
Apples and oranges.