Again, let's please be precise, not return to imprecision. For the individual, it is a local maximum. For the population, it isn't, it's a trap/local maximum. However moving whole groups to new behavior is insanely tough for a simple reason: culture-retainment (cognitive herding) is high in the list of what humans do best, for good reason. Ironically perhaps, the history of colonization provides the best evidence of how to initiate change. Building a new prestigious culture within the old one does work. Maybe not in a delightful direction, but it has been demonstrated to be effective.