I can't answer for Larry Parker, but I will answer for Terry Parker,
Plain and simple, form follows function.
Breed to the highest standards you are willing to keep and don't let pretty cloud your mind and after a long enough period of time, form follows function.
Let's say my English and Irish peasant forefathers needed dogs that were silent, super fast and all bidness in order to aid in the survival of their families by way of catching rabbits and other small table fare that could be quickly aquired, skinned prepared and eaten. This was the case becuase in the feudal system all game belonged to the nobility and poaching was highly frowned upon.
Now, knowing what he needs his dogs to be capable of and knowing which dogs in the lords lands are the best coursers, it would make since that he and his fellow peasants were breeding best to best and eventually a certain conformation came about.
What if the men of old really really liked the look of the big fat blue bullies of today back then and decided to try to make their dogs achieve that look? Would they still have churned out the greatest high speed Poaching dogs the world has ever seen? Or would they have been sitting there spinning their wheels and not getting anywhere because no matter how much you want it to, function doesn't follow form. Form follows function.
Bob Owens says Pretty is as Pretty does, once you understand what that old timer means by that phrase, all this nonsense becomes common sence.