> many periods, even for centuries on end, had almost no change between generations regarding lifestyles

Many of the instances where we have records of this being a recurring complaint of adults toward the youth were in those times of little apparent lifestyle change; part of that ia that the distance of our perspective probably minimizes changes that were perceived as significant in the local context, but a bigger part is that, while objective changes in lifestyle or technology can provide something to tie the complaint to, the main driver of the complaint is not the change in society but the change in the observer’s position and perspective within society.