It's unlikely that distilled water would have any benefit, but cleaning regularly could help.
The case back corrosion is caused by the movement of the case-back gasket, which rub away the Stainless Steel self-healing film that it develops. This exposes the unprotected steel to the effects of the environment. Sweat and body oils are also toxic when they contact the unprotected steel surfaces.
If folks had their watches serviced more regularly, which would have cleaned off any beginning corrosion that was taking a foothold, and fresh, greased gaskets installed, they would likely still be in excellent shape.
