At least my dog's sire's line had some performance titles (including a JH), so you know they weren't brain dead (and at least I was careful to meet her parents and grandparents). But I've seen plenty of conformation Labs that were so dumb, you wonder how they remember to breathe. Fortunately mine is smart as a whip (TOO smart - she can open doors, cabinets, and tupperware), she loves to swim and even to swim in the surf (we have a picture of her surfing down the front of a good sized breaker with a bumper in her mouth) and she's very birdy and gun staunch, so her show blood did her no harm. She's probably not as keen as a pure field dog would be, but she's good enough for an amateur like me. I went to an Evan Graham seminar this past fall, and he used her as a guinea pig for a couple of training exercises, and opined that she was a very sensitive and intelligent dog. (He also advised me just to keep the collar no higher than a medium 1 on her after we got her conditioned -- that's all she needs and I use it sparingly.)
I'm not serious enough to get into the field trial biz, UKC hunt tests are more laid back than the AKC and just about right for a dog and handler who are coming to the game late and wet behind the ears (friend of mine in our hunt club says that AKC judges take positive pleasure in busting people at the JH level - of course his dog is SH and winding up her Finished title in UKC, so what does HE have to worry about? She runs agility too (with his wife) and is a splendid dog, the same height as my Shelley but longer in the back and about 55 pounds.)
I've got a lot of respect for folks who work the swamp collies. We've got a couple of Golden fans in our club, one very serious trainer is taking her third Golden to the Grand . . . and you're right, that's doing things the hard way. A couple of Chessies (great dogs) and Flat Coats (great once they settle down) in our club, too.
One of the funniest bits I ever read in Golden Retriever News (I subscribe because of the great performance training and veterinary articles) was written by a couple of conformation gals who showed up at a hunt club training session with their perfectly coiffed Goldens . . . " . . . everybody was driving pickup trucks and wearing camouflage, and their dogs . . . their dogs had whiskers!."