[gpm]

Driving for hours in heavy rain results in pretty continuous actuation of wiper motors. I'm far from a mechanic but I can't say I've ever heard of a wiper motor failing either. I'm sure they have real data on it instead of this handwaving, but as an outsider I would be surprised if it was an issue.

[Frondo]

Not a comment on the ventilator made from a wiper motor, but I have had one fail, and had to have it replaced for something like $255.

All mechanical parts will fail (the antikythera device isn't still operational, but that's a pretty long-lived device!), it's just a matter of when and why.