Maybe I miss read but I don't see how anybody could say you should never need a outcross.
I don't think you do if you have what you need in a family of dogs. I'm not suggesting you can start with a single male and few females but in a good sized family it would be ridiculous to breed out if you liked what you have. Everyone needs to be looking to improve but it doesn't have to an outcross to strengthen the family if hard hunting, hard culling, and demanding breeding selection is taking place.