Too many variables....riding style, engine mods, maintenance, etc. There are some high mileage EVO's as well as TC's out there with stock clutches still going.
I have a 01 FXST with 48000 miles I purchased new and the clutch is still strong and showing no signs of needing replacing. I ride hard but do not beat on it and am very meticulus about its maintenance schedule. I think again there are a lot of variables.
Properly adjusted and applied,a wet clutch will last a long long time...even with heavy use..a motorcycle clutch is designed to be used much 'heavier' than an automobile clutch.....