Most puppies will be able to do most of the work required of a WC Test at 10 to 12 weeks of age.
I've seen videos on youtube re WC test and that looks very basic and sort of what we taught the dogs in class years ago. It's stuff I think any retriever will do. Basically direct retrieves and unlike with obedience where you send the dogs and wait for them to return with you standing stock still like a statue, I heard the owners repeatedly guiding/calling the dogs as they were coming back. And the dogs weren't even sitting when they got back. <= I hope I wasn't watching the wrong videos, but that was stuff that I think most dogs can do without much training. o_O
The issue that pops up though is I'm friends with people who do field and that's their focal point. So the puppies ARE getting their mouths on birds very early. And the owners have access to working fields, ponds, guns, and training buddies where the dogs are really used to all of that stuff.
Where you have disconnect with people out there is retrieves are very easily broken. It's one of the easiest exercises to totally mess up as an owner. And the dogs learn the keep away game or they learn they don't HAVE to bring stuff back to their owners.
The other issue is I have friends in conformation who have very high energy goldens and these goldens have not received early training that most field and obedience dogs get as puppies. So my friends literally turn white as a sheet when they see a dog off leash in an uncontained area, because their experience with their dogs is they will run.
A lot of old field people put a lot of blame on the dogs for not being what they should be, but owners bear responsibility. I've seen it in obedience. Actually there is somebody very close to me who drives me nuts because she bought a dynamic dog. This dog was a DREAM dog. Super smart, very owner focused, very eager to please, eager to work, etc.
And this puppy is going on 8 months... and he still hasn't been taught any off leash work or stays.
And this owner is terrified of taking her dog off leash, because she's rightfully certain that this dog will just run.
This owner, you can't put all the blame on her. It's where she trains.
But back to what I said before - if training clubs put an effort into getting more people with puppies comfortable with doing WC tests. I would not have a doubt that more and more goldens out there would have these certificates. And the very least you would have that on conformation dogs, as the owners would be putting that much time in. Maybe not everyone, because people do not seem dedicated as others to training their own dogs in anything. But you would get more cross over if there were more easy access. But if field people cross over to get CCA's done on their dogs. I'd say that with more access (at training clubs, more diversified ways of training, less shock more fun), that you would have more show people getting WC's on their dogs. Which I believe those are the equivalents.
If it's something where they can reasonably train basics and "rehearse" the test through classes at a training club. It can be done. And not just morning classes for retirees and homemakers...
That said, doubt it would draw everyone I can think of... some people already have access to obedience classes, and they don't them with their dogs. They barely make it for handling classes if they do. A lot of the training of the conformation dogs is done by pro handlers. And there is training involved....