Maybe the inquietude that gives birth to sad reflections about the perishing state of things is caused by their permanence.
It is the permanence of a thing that refuses to be for something or someone else. By perishing, the thing retreats in itself, so that it dies maintaining a permanence of its own being, even by ceasing to exist.
The perishing things primary left the men who want to keep them and only secondary go out of existence.
The grief for a perishing thing is an affirmation of one’s paucity in subsisting himself as long as the permanence of the thing seems to do. It is the sufferance of not being able to subsist by himself as the perishing thing does.
Moreover, the exposed sufferance about perishing things is a way of acquiring the permanence and also profoundness from them. There are rather rare those human voices capable to be sufficiently strong for being heard as means of revealing the things in their dying permanence. In most cases, when the things are mourned, the voices become weak lamentations of the impossibility to reach their permanence. And they reveal only the weakness of the mourner.