do superchargers ever just break and cant be fixed

roots or centrifugal?

Centrifugal blowers usually get screwed up when something in your engine breaks, then the debris get's pumped through the oil system of the blower. I know some centrifugal's have their own seperate oil system to fix that. Also, they can get messed up if a rock gets past the air filter and hits the impeller.

A roots blower is probably a bit more dammage resistant because the speeds are not as high.

I know I could find a way to break anything beyond repair, but blowers are expensive and the common failures are usually less expensive to fix than replace.