I have, for most of my life been confronted with shoveling snow from our sidewalk  in winter.  We have used up many different snow shovels - sometimes getting wider ones, shorter ones, different handled ones.  But one thing remains true about all of them - they all wear away over time but in the same pattern.  A protrusion at one end, a sweeping outward curve to the middle then the pattern repeats to the other side.  The least abrasion occurs at the point where all the pressure is applied.