Harry was extremely reactive and filled with nervous energy. His breeder doesn't breed for extreme dogs, but they happen. I don't think all of the calming exercises in the world could have gotten Harry to chill out. It doesn't make for a nice pet, but they make for dynamic competition dogs, which is why they seem to be getting more and more extreme.
That is a bit different from selecting for such dogs generation after generation though. IMO breeding generations of dogs who have to live in kennels because no one can stand to be around them (or maybe because they tend to bite their people) isn't all that different from breeding for dogs who are put together so oddly that the general public thinks they're crippled or bird dogs who have to be trained with e-collars to hold a point instead of chasing and killing birds. It's all selecting for traits that shouldn't be part of the breed and historically are not but which give one an edge in their chosen competition.
I got a dog that is EXTREMELY driven and like Stafinois said, they make for great competition dogs, not so great pets. I have a little APBT puppy now and her drive fails in comparison to him but she is much easier to live with. However, I have described her to friends as not having a lot of drive and being lazy, they said,"Courtney, she has plenty of drive and works hard, she just isn't extreme like Judge." A dog like Judge will ruin your perception of drive in others. LoLa(APBT) is far more balanced in her drives and although I'd like to see a little more drive all the way around, she is an awesome sport dog.