Or bodies are in a constant state of getting older and undergoing collapse. I think that believing in the good old days is a reaction to getting old. I think that believing in some golden past is it reaction to our own bodily degeneration. Fear of our mortality is a powerful force, and I think that a large amount of people externalize/project that fear onto their perception of society.
I prefer the 'ole $sudo dd -i /dev/random -o /dev/sda