'Wear' is a result of movement/friction between the two surfaces.
So, three factors come into play:
1. How well the gun 'fits' the holster.
2. How well the holster 'fits' the person.
3. The materiel the holster made of.
It is my observation that the first two are more important than the last.
I say this because if the 'fit' (X2) is right movement is minimized and thus wear is minimized.