I'm afraid that's not completely right. The SNES carts use Mask ROM chips which are extremely cheap and were burned in the very factory! This kind of chip isn't erasable; yet it can be damaged (and I suppose you wanted to say that) by static charges.
Of course a cart can go haywire in any case :) Imagine a 30 years old SNES cartridge (some day :)... I wonder if it still works after "hard usage" over time...?
-Cyan