Nostalgia is a lingering feeling of people. The reason why nostalgia lasts forever after being washed over the years is not because it has much charm in itself, but because it can provide people with material for reflection, so that people can trigger the perception of life or draw power from it in the process of some kind of drastic or broken change that people have experienced or are experiencing.
The reason for nostalgia is that old things have a specific positive effect on people matches the content of this passage.