I'm pretty sure this targeted at the fact that larger dogs in general live shorter lives than small dogs. I don't think this has anything to do with the genetic issues caused by some breeding.
Giant dog breeds humans have made rarely have such long life spans, with dogs like Saint Bernards, Great Danes and Irish Wolfhounds living 8 to 10 years.
That is living indoors, with access to regular medical checkups, and without parasites.
FWIW Wolves are huge, up to 160lb.
Wolves in the wild are lucky to make it to 7 years. A 12 year old wild wolf is exceptionally rare.
But 7 to 8 years is the upper bound of many large dog breeds who are pampered and have excellent medical care.
There are many large dog breeds that will never make it to 12, but a pampered wolf will.
My overall point is that even for the overall category of "large canine", we've reduced the lifespan of domesticated dog breeds.