Joe your post is 100% logical and makes perfect sense. But there is not an A-List pro in the country that would turn down an "Auggie" or other dog they think will bring them more wins and the best shot at a National.
Farmer runs up to 19 Open dogs a weekend.
Even though his truck is full, you approach Danny with a big time dog that he thinks he'll win another National with... he'll put Ethel in the front seat and make a hole for your dog and have 20 at the next trial. Applying your logic, Guthrie is going to think that is to many dogs and his dog won't get enough training. He'll pull his dog. Viola - back to 19 and you've just improved the truck as a whole.