We're discussing fans which are motors with plastic blades attached to them. I would love to see the validation plan on most of the parts (fans especially) marketed as high-end. I doubt they have run them long enough to be anything near what an OEM part goes through.
Rods and rockers inside of their design spec, the OEM ones basically last indefinitely with good maintenance, so it's highly dependent on application.
More money doesn't equal better.