Standard turbos are great as paperweights.
Back to the guys original question- A manufacturer would be crazy NOT to coat as much as possible with ceramic if it indeed 'never wore out', just think, they could claim to have the most durable, longest lasting engines of any manufacturer! But, in the world in which we live, if something rubs across something else (especially with additional heat being supplied), things are just going to wear down eventually, lubrication or not (geez, sounds kinda sexual, dun it *LOL*)