When I see some of the old youtube video on dogs from the 30s, etc all I see is crappier training. Nothing to say the dogs themselves are any better. I do believe that, in general today, more people are breeding just cause they can instead of for the good of the breed as a working dog. That can put more crap in the gene pool.
Agreed, Bob!
With regards to the Busecker Schloss line, Alfred Hahn was one of THE breeders in his time. He attended all the shows, read all the Körung reports and books, noted all the offspring of the stud dogs and would never breed from a dog that had not much pigment. He combined lack of pigment with lack of nerves. The Dutch Breeder Koos in an interview said that Hahn liked "dark coated dogs". He didn't only like them, he would only breed from the well pigmented dogs. I think that Koos has followed in Hahn's footstepts.
Hahn commented on the show line breeders who just need a SchH 1 to breed, and at age 2 can be mated to, thereby increasing the "turnover" rapidly, compared to the "greys", i.e. the working lines who he and his colleagues tested apart from the SchH and, when they had reached Europen or nowadays World level were 5-6 years old.
He also considered the dam's quality as important as that of the sire (Mendel).