The type of metal does have an effect on strength/wear.
There is something called the Vickers hardness scale. Generally nickel/silver frets are rated at HV170 (softer). Stainless steel at approx. HV 300 (harder). Different manufacturers of fretwire can vary.
So fret wear isn't always about the string used.
dang! so it can actually be the fret wire used from bass to bass?