I think there is some truth to that tash, but the different breed tendancies of purebreds are instincts that have been bred for years to do certain jobs etc. I love german shepards, growing up we had a lot of them throughout the years, they are a dog who needs to be outside a lot and they naturally just arnt as patient.
Our lab on the otherhand spent the first year as a kennel show dog, and several years alone with tom. Yet despite being older when jasmine was born, he has been the most patient, lovable dog ever, the kids can seriously do anything to him he he has never once growled or shown any aggression. Becausew labs are naturally bred to be patient and calm.
Since my mil breeds high quality labs I've seen tonnes of kennel and breeding dogs who all show the same personality. We've seen labs come back from neglectful homes, labs who've been kennel dogs for years etc and they are all super amazing dogs.
Some breeds just arnt as patient or calm no matter how they are brought up.