Are you saying medieval Germany was richer than present-day Germany or USA? That's of course not true. And it's also not clear why you call it a survivorship b

Are you saying medieval Germany was richer than present-day Germany or USA? That's of course not true. And it's also not clear why you call it a survivorship bias - these villages were probably above-the-median in their days, but it's not some singular building like Pyramids that is not representative of overall building of that era/territory. It was just how the houses were built there and then.