The answer to this is 2 parts, the plastic we use and the design of the baits:
1.) Like all soft plastics, they aren't indestructible, we do use a very hard formula though, so they're at a minimum as durable (probably more so) than any other soft plastics you're used to.
2.) The way we've designed them, wherever you grab the curly tail and pull until it breaks, it will break right where you're holding it, instead of the whole tail popping off like most curly tail designs, and once you do finally wear the tail completely out, boom, you've still got a jerk shad to keep throwing!