faulty logic.
i say this again and again.friction causes wear,NOT hardness.just because ss is harder,that does not mean it wears your strings quicker.as a matter of fact ,if ss is highly polished,it provides less friction than nickel.when you rub two substances together,the softer substance wears first...but not necessarily faster than against a similar,but less dense material than ss.
but even if that WERE the case,it would not make a difference anyway because strings tend to break at the saddle or at the pick attack area.and how long do you want the same dead set of strings on your guitar.
but believe what you want.i don't care.