If you are just doing performance testing and not evaluating your purebred breeding stock for structure and type, then you are doing a disservice to your breed. The entire purpose of the conformation dog show is to evaluate breeding stock for structure and type. If your structure is only okay, but you have a breed that has a high pain threshold and/or high work ethic, you may have a wonderful performance dog that breaks down in middle age instead of old age. If you dont have enough type to look like the breed you represent, then what is the point of breeding purebred dogs! There are plenty of mutts out there who can excel in performance events, but if you are going to breed purebred dogs, this should not be the only thing you are interested in.
Form follows function. A dog is not going to be able to do its job if it is structurally unsound, just like a truck wouldn't be able to haul anything or a race car would break down at the track if they were structurally unsound. The idea of "purebred" is a very new idea indeed in the very long partnership we've had with dogs. If it could herd sheep, it was a shepherd. If followed game visually, by scent, or down into the ground, it was a sight hound, scent hound, or terrier.
Where in the world did you get the idea that high drive dogs break down in middle age? That's completely counter intuitive. I know a LOT of working dog handlers and breeders from this country and worldwide. I don't know of a single one that randomly has dogs "break down" in middle age. The breeder of my 100% working lines 10 month old Belgian Malinois puppy has her dogs working at French Ring until their teens. I also know one of the breeders of some of the highest drive working dogs in the world who breeds Dutch shepherds for KNPV (the Dutch police dog trials). She likewise has her dogs working until their early teens. Working ability, by definition, must include longevity. It does no one any good for training police, SAR, military working, assistance dogs, etc if they go through years of training and can only do their job for a few short years.
Any dog that is to be bred should be a good representative of their breed. To me (and many conformation folks) this means that they should be able to excel in the conformation ring as well as the performance ring. Conformation is not for nothing. Its like a cursory test of breeding fitness.
So I guess super models are just the pinnacle of the human race, eh? The cursory test of breeding fitness is being washed, groomed, and run around a ring? Wow. That says little if anything to its temperament, health, intelligence, or working ability, the true character of the dog. And please read those articles I originally posted if you haven't done so. They are very illuminating as to the trends and fads in the show ring, breed standard be darned.
My example of this going the other way is the rhodesian ridgeback. They are supposed to be a utility hound (sight and scent). They are supposed to be a dog with bone and substance, but the recent focus on lure coursing has driven the breed toward a faster looking type. Consequently, the breed as a whole has lost substance and gained tons of size. They look more like salukis every day. The focus on one part of performance with leniency in conformation has lead to a change in the breed that detracts from their overall purpose. This dog is supposed to be a protector, and I dont know about you, but I would rather have a real RR working as a hunter/guardian than a saluki-esque one.
I'd rather have a Saluki-type dog to protect me that was actually challenged with some sort of work that requires more than sleeping in a kennel or on the couch except when it's time to get in the van for the dog show than the equivalent of a dog that looks like a Ferrari with the engine of a Volkswagen.
Now, that being said, I agree that GSDs have become very extreme and even conformation labradors have become so thick that they would be useless in the water and many many breeds have too much coat to be any good in the field.
Most conformation labs couldn't track or retrieve their way out of a paper bag. 🙄
Oh, and the truth of the matter is that nowadays, very very few dogs are used for the purpose they are originally bred for. I have akitas. I dont intend to go bear hunting any time soon, but I think they are beautiful and the sounder the better. I dont want to do Schutzhund with such an independent breed because they are not as biddable as other protection breeds and make decisions independently (much more so than a GSD or Malinois), so its not technically an appropriate test of performance. We do not have a performance test currently in our breed that we use to evaluate performance, and we dont use them for performance anyway. Conformation is therefore our best test of breeding stock. Since mine are companions, I do CGC on everyone and TDI on temperaments that are eager to approach strangers (not a "correct" or typical temperament in the breed, after all they are guard dogs). I do obedience with mine, but more for fun than anything. I would not breed to an akita with poor conformation who happens to be particularly good at obedience. If I want an obedience dog, I will get a golden or a border collie.
I 100% agree that your average owner should not be owning a working lines Malinois. 
However, even from the finest bred working litter, some of the pups are just not going to have it. Just like some show line pups, even if their pedigree is peppered with "champions," are not (fill in the blank) enough for the show ring. Make sense? That's perfect for folks who want a well bred dog with solid temperament and health from appropriate health testing, but who would like a fun active companion and not a world class military working dog or search and rescue dog.
Akitas were bear hunting and fighting dogs, yes? Why not have them do tracking or agility or carting or rally, for instance? Most people don't have a flock of sheep to herd with their border collie and Aussies, so they do agility. Most people don't hunt rabbits or badgers in holes, so they do Earth Dog. Most don't need to do live coursing with their sight hounds, so they do lure coursing. Most people don't want to fight their pit bulls, so they do weight pull to test gameness. For most dogs and their original job, there is some kind of sport or working sport that can substitute for their original purpose to test that they have more than just fluff between their ears. And certainly, like you said, definitely get those CGCs and TDIs. That's certainly a good start. 👍
As far as akitas go, I think that they are absolutely stunning and have come a LONG way in temperament over the last 10 years or so (esp in show lines, dont hold the puppy mills against us). People are naturally attracted to extremes in type and that's why the breeds exist. The dog fancy is called a "fancy" for that very reason.
By acquiring a purebred dog, I know what health conditions I am dealing with, I have consistency in type, size, temperament, etc. Im not saying shelter dogs are bad, but I am saying that the dogs in the shelter probably should never have been bred in the first place.
I'm saying that the majority of purebred dogs shouldn't have been bred in the first place. With breeding only with conformation in mind (which is what many show people only do!), that's precisely what you get. Trends and fads in looks that sorely lack in character, temperament, health, and working ability. Once again, is a Ferrari still a Ferrari if it has a VW engine in it, even though it looks like a Ferrari? NO WAY.
That's why I show, and that's why I will breed. To preserve, protect, and promote the breed I love.
Least you get the wrong idea, if people wish to show along with doing some kind of work, working sport, or sport or other activity with their dog, by all means do so (I personally find it boring), but let us have no illusions that the conformation ring is some sort of end all be all to what makes a dog even remotely worthy of breeding. It's no more a true test of the character of a dog than a beauty pageant is a test of the character of the girls who compete. Heck, they even to have some sort of talent competition at beauty pageants, right?
