Yes dogs CAN survive on low quality food, but that does not mean they are in perfect health, and that is not something you can judge just by looking at them.
Vela,

Since one can not judge perfect health by looking, what is your criteria for judging whether your dog is in perfect health? How do you determine this? What are your specific metrics and diagnostics?

K9soul,

I have no idea whether the Propet dog food I feed my dogs is considered sub-par kibble or not. But in answer to the comment in your link:

No research has been done to determine the long-term effects of feeding kibble, nor to determine if it is actually healthy for your dog (it is just assumed healthy because it has passed a 6 month feeding trial, and then manufacturers falsely advertise their product as healthy.).
I believe my previous dog which lived till 11 yrs of age, and the current two at 3 years of age far surpasses a 6 month feeding trial. I have no idea as to what the latest health claims Propet may be making for their product. What I do know is that my dogs flourish on the food. Mine have never had seborrheic cysts, bladder crystals, or persistent infections. They have never had a raw diet either. Now how do we explain the absence of these problems on a commercial dog food diet?

You do realize that Collies are genetically prone to skin disorders, not to mention Progressive Retinal Atrophy, and Collie Eye Anomaly a syndrome that involves one or more of the following: retinal degeneration, cataract, and retinal detachment? That's genetics not food. In another words you could have gave them a steak every night for their 13 yrs, but that would not have changed the genetic make up of the dogs.

P.S. Yes my previous dog enjoyed frosty paws- almost as much as a bowl of ice cream.