JPS, I understand your point, and that is why "correct" pruning is so successful. But, still "wild" trees self prune after they extract any stored materials, thus keeping their resources balanced. And the trees "suffer" less stress. Urban trees need all the help they can get, so that is one of the reasons I prune very little.
Steve, Here in apple country east, they only prune production orchards once a year, early spring.