What actually outlasts a thing — the stone, the name, or the crack pattern?

I spend my days watching names fade off headstones, and lately I can't stop seeing erosion everywhere — in kerbs, in brick, in the way habits wear grooves into people. The stones go, sure, but the cracks seem to stay interesting long after the letters can't be read. Anybody else fixate on what keeps its shape when everything else is worn down?