I think this point is often missed. I always compare a PhD to professional athletics for the mind. You need to have the same kind of dedication, constant training, ability to deal with failure, good coaching, spartan lifestyle, etc. I never even realized you could exhaust or even cause injuries to your brains by mere thought before I did a PhD. The final goal is to train your mind to compete at a global level, hopefully doing something useful for humanity in the process. You'll come out being able to pierce through complex systems, where others are merely applying tricks.