I've always thought that the difference between a sport like field and a sport like obedience is that when you do field work with a dog, you use the traits and instincts that the dog already has and typically when the dogs are out there and they know there's birds out there, all the lights are on and gears ready to go.
NOPE
It's not all instincts.
YES we actively choose dogs who love birds, have good eyes and can mark, and want to swim, and all that jazz. The retriever breeds are uniquely designed to have good eyesight and the seek-and-find and bring-back-to-the-pack parts of the carnivore hunter behavior chain is intensified. They are physically suited to their jobs, long legs and boat-like bodies to breathe easily while running and be buoyant. They are also incredibly biddable and pliable because their job is working alone with their owner to hunt and taking directions from the hunter, not independently finding game away from the hunter like a spaniel, setter, pointer or hound. That's that "non-slip retriever" we hear about.
In the basic level field events (Junior Hunter & WC) the dog IS basically running off instinct. It's very little training involved, and all the handler does is let them go and grab the bird when the dog gets back with it. The dog is on it's own to find the bird.
In advanced field work (Senior on up) it's a whole nuther ballgame. YES we expect the dog to mark and find the birds with their own faculties. They also have to learn marking concepts, see pictures formed by the terrain, and understand how to properly navigate these factors to successfully retrieve the mark. That is ANYTHING BUT instinct. The only instinct there is to be biddable to the handler. In fact, most of what we ask them to do is completely UNnatural and totally against their instincts. Sit quietly until sent? No way, they want to take off immediately. Stop and take direction from the handler? No, they want to run around like an idiot and scare up birds. Take a straight line through water 2 feet off shore? Well that's dumb, it's way faster to run around. Those are just the easy examples. And remember, in competition, they are asked to remember these things on new ponds and fields they've never seen, that are completely different than any other place they have been. They have ten seconds to evaluate their surroundings and understand what is expected, to generalize the concept and apply it. FAR from instinctual. But they get so good at this, experienced dogs can "know" a test without seeing a single bird be thrown. Ask me how many times Bally has headswung off the long gun before it was in the air, only to absolutely step on this retired bird when sent for it. He recognized the setup and knew which way the bird was going to be thrown, because he's seen it over and over and over in training, albeit at a different field, but one look at the guns and he knows the setup.
When I say you can "see gears turning" with a good advanced field dog, I don't mean they have a big motor and they crash through the field headlong after birds.
I mean you can tell the dog is thinking, evaluating, adjusting and being very careful about their choices in how they retrieve. They will correct their lines if they realize they aren't making the right choice, en route to a bird. It's quite amazing actually.
So imagine my eyes glazing over when I see dogs that just are not focused on their owners at all. Or if they are, it's the barest fraction of what I have and value in my dogs. I acknowledge that a huge chunk of that is foundation and conditioning.
I see what you're saying, and understand. Field dogs (both labs & goldens, field trial pedigrees) CAN be very environmental and reactive. It CAN help them in the field. It can hurt them in obedience. What makes them see every inch of a bird 400 yards away also means they notice a shadow on the ground in the obedience ring that distracted them when other dogs didn't pay any attention to it. They may be more fight-or-flight reactive, to a startling sound, which is not great when you want a bombproof obedience ring dog. A friend of mine bought a field labrador for obedience and can tell you all about this....and she won the NOC with him. BUT --- a lot of that is training. If you buy an animal like that you have to mold him into the picture of what you want. Maybe these people just didn't want that picture. They wanted to do field work and dabbled in obedience. Who knows.
My BF's older Golden is field trial pedigree. She is the LEAST trainable and biddable dog I've trained. You train her an hour to get a minute's improvement. She's impulsive, reactive, spastic, lightening fast and literally cannot think straight when she is amped up. She is VERY DIFFICULT to train in the field. She has a very mediocre field record to go along with that. She didn't have the best foundation of training (basics glanced over), and she literally loses her MIND at field events and marks like garbage. It's REALLY difficult to get anywhere with this dog. My show goldens are a thousand times easier to train in the field. She had her CDX with all first places and high scores before she was two. Obedience was so boring, and so non-rewarding, that she could think straight and was happy to do tricks for treats. Very deceiving!