Positive training is a super-motivational method that works great when the dog wants to obey. That is, when the reward from the owner is more interesting than the surrounding environment.
However, it does not prepare the dog for situations when it doesn't want to obey a familiar command. This happens when the environment is more enticing than the handler and their rewards (like aggression, hunting, protection, etc.).
Positive trainers have a theoretical solution for such situations. The environment is too distracting and difficult, so you need to train in simpler situations and gradually move to more challenging ones until you achieve the desired result.