Hmmmm. Sort of understand what you're saying...but totally disagree with you.
I have only ever bred 3 litters and each pup was spoken for before they were born. I made it my business to ensure I had good homes for at least 12/13 pups before I even contemplated lining my bitch. I would feel incredibly uncomfortable 'culling' strong, healthy pups just because I hadn't got off my arse and done the groundwork in ensuring the pups all had homes to go to BEFORE conception took place.
Similarly with failed workers....unless there's some hideous trait in the dog's character that makes her a danger,