Some of those subjects were works of nature but many were works of man -- old barns, farmhouse, fences, and so on. Although these things lasted for 100 years or more, every single one of them had been destroyed within the last decades -- they were all gone by 1987.
I think that it is a pity that we in North America are so cavalier about our natural and man-made heritage. In Europe there has been for many years a serious effort to preserve the family farm and to preserve man-made works of previous generations. Such a commitment to preservation requires us to pay attention and to pay for it. The Europeans consider it a worthy cost. We North Americans apparently don't and so our heritage disappears, very often through carelessness and more often through greed.