I have them on Addams Family and Fish Tales. No noticeable wear on either - after 2 or 3 thousand plays on each.
I see them on route all the time - dirty ones that have been there a *long* time. I've never seen wear.
I think you got a bad set. The only other thing I could surmise is that maybe your balls are really old/chipped/scratched and wearing hard on the rubber?