It is easier to find a well bred pup from one of the Big 4 pointing dog breeds (Pointer, Setter, Brittany, GSP) because there is a much deeper pool of breeding candidates.
It's also easier to find a poor specimen.
Rarer breeds around here seem to be bred far more carefully.
So I disagree with your generalization there, too.
WRT generalizations about breeds... They tend to be accurate, as long as you understand that dogs are individuals. Breeds have standards, and dogs are bred to fit them. Individual dogs of course vary.
For example, Vizslas tend to mature later and to be very vocal and histrionic, but also more interactive with people, GSP's tend to be more aloof and start focusing on task at an earlier age. I've seen some variation in individuals -- sure, there are a few Vizslas that shut up occasionally and there are some very affectionate GSP's. But if you are involved in dog training and testing, and you see a hundred dogs of different breeds in one place, all bred for hunting, you find that breed characteristics are not horse**** at all.
Also, GSP's tend to retain a dog smell due to their thick undercoat, but they're fairly well-protected from cold and abrasion. Vizslas are easy to bathe, but "thinner-skinned."
Are their pointing Labs out there? Yes. Do they have the big-running endurance of the VHD's mentioned in this thread? No.
Are their Vizslas that people use for goose hunting? Yes. Will it be easy to find one that sits still in the cold blind? No way.
It's cool when people get lucky with a particular dog, especially if they discover they also like a different kind of hunting than they got the dog for originally. However, getting a Lab for pheasant or a Vizsla for goose is trusting that your dog will be
different from most members of its breed. Any dog is a little bit of a gamble, but getting a dog specifically for what it's not supposed to be is a gamble with lousy odds.