I think I see the situation for Baskin.
The lord of the manor, Lord X (let's say) has a shoot, and enjoys shooting himself. he has two good working dogs who perform well and are much admired by the local people and people who pay a fortune to shoot during the season. Lord X wants another working dog, and wants a pup from his two working dogs (and I think quite reasonably). He has had them for years, they are healthy and good tempered, and he will take the pick of the litter and knows he can sell other pups to either local people who want a working dog from his strain, or the other people who come on the shoot who also want a good working dog from this proven strain. So he can sell the unwanted ones, quite properly, to people whom he knows are responsible and who want a working dog. This is working stock primarily. This is how it would work in the country, on farms for sheepdogs, etc. Do we imagine hill farmers etc go to pounds or 'reputable breeders'. No, this is for we non farming (city sometimes) folk.
This is not what we mean by irresponsible breeders is it, surely? I mean puppy mills, where dogs never see a home environment or outside a breeding crate, pups not handled or socialised.
Re the expensive tests -can you please elaborate on what these are, who does them and what they cost? Genetics can only show a possibility, a likelihood of carrying/getting a defect, not a certainty. For example, i think Lord X would know if his dogs had hip dysplasia or entropy of the eyes (or whatever) because they are old enough to manifest it. He's know if one was vicious or nervous. But lame blind scared savage dogs wouldn't make good gun dogs anyway.
I can't help but feel Baskin is being picked on here. There are pros and cons of neutering. If she doesn't want to she doesn't have to. Like we decide on whether to have immunisations for our children. She has to do what she thinks is right. And she lives out in the country. If I had to put my money on a dog from a rescue being a problem, or her dog, i know where my money would go.