It can be fixed with better training, infrastructure changes, or both. The cost of fixing the training regime would be extremely high, however: New drivers presumably already know what to do and have been tested on it during their practical exam. The problem is that encounters with stop signs are sufficiently rare they fail to naturally reinforce that training through repetition. To fix that, you either need to increase the frequency of natural stop-sign encounters by installing more of them or to introduce artificial encounters by requiring practical exams for license renewals.