Dog shows

My wife likes to watch dog shows on Animal Planet. Sometimes they're interesting. But I've always wondered why they don't put the dogs through any kind of skill test...kind of like the talent contest in beauty pagents.

After all, these dogs are being judged to see how they compare to the breed standard, and most dogs are bred for a particular purpose or task. So how can a dog be judged best of breed if they don't test to see if the dog can do what it was bred for? Sure, a dog can look good, but what if it's dumb as a post? Some best of breed that would be.