My only comment is an odd ball one, I wonder if the release bearing had some friction? Not enough to make noises or cause operational problems but enough to cause wear every time contact was made.
All the thrust races of the bearing type I've seen are pretty hefty items and could easily cope with the small amount of extra spin permanent contact would give (bearing would not be spinning when clutch not pressed etc).
Clearance is needed though on the three wheeler - that has a carbon release bearing and the less work that it does, the longer it lasts.
