A quick point on size and dog shows - I think you're both right. Over the decades kennel clubs can and do adjust standards and what were largish dogs a century go in their natural working form can become gigantic freaks (great Dane a good example) but conformation standards actually keep a lid on this to a degree, the worst offenders are dogs not bred for shows but bred for cashing in on hype. Breeds like boerboels and boz kangals have put on 50 odd kgs in the last 10 years, which is obscene and totally unrivalled in the dog show world.

Of course, real work is the most reliable way to keep a lid on it. Boerboels working on African farms in the way that shaped the breed originally sure as hell aren't going to survive at 200 lbs. Likewise for the dogs of Turkish sheep herders.