I don’t think you can blame naïve dog owners, because they don’t know what it means to get a working dog.
The fault lies with the breeder, because should know that only certain people know how to adequately handle such dogs.
And even if you don't consider that an adequate warning, after Marley they got the SAME kind of puppy again, and had the SAME problems all over again.
The only thing you can do with a dog like that is put him in hard training. A few 200 yard marks and a 90 yard blind early every morning will turn him into a good little citizen.
Before I run my little black dog in a hunt test, I take her to a high school football field or out in an open field somewhere and run her on a couple of 100 yard blinds just to settle her down.
Marley's owners weren't willing to do what the dog needed. I feel sick that the poor dog suffered so much with his high-octane temperament and energy and nothing to use it on.