Swack, I'm not sure flowing coat has a lot to do with it. I don't know if a Golden Retriever has ever been BIS at Crufts, but I'm not sure a Golden has ever been BIS at Westminister. If he has been, it was, I think, Cragmount's Hi Lo http://www.k9data.com/pedigree.asp?ID=455 You'll note he was born in 1962. They have only rarely gotten to Group I at Westminister.
The trait that makes them popular numerically in registrations has a lot to do with their temperaments for family needs and intelligence for training, not just field training, but also obedience, etc.