If Fan-Tastic vent lids/covers have a lifetime warranty, then how come there are so many for sale at RV supply houses?
With a lifetime warranty you should only have to call for a replacement like we did with the original founder/owner.
Not sure what you are asking, but there are a lot of RVs out there with tiny little fan blades that are essentially useless. We just replaced our Kool-matic with a Fantastic vent since we had great results with them in previous coaches. We don't expect to replace it in the next twenty years. Their customer service gets a A+, without going into a lot of detail.
What I mean is the company got sold, and things are different now.
The top vent cover on our bathroom fan cracked where the metal roller track mounts. The fan & housing are NOT Fantastic, but I had to buy a "Fantastic" fan cover in order to get the metal roller track on the side---like Fantastic makes/uses.
So most bathroom fans probably have the Fantastic configuration when it comes to the cover. But, if the typical RV owner does not have a Camco shroud over the vent, and the vent cover is open while going down the road--then the wind buffeting the vent cover can cause the metal track to break off. Hence, a lot of "Fantastic" vent covers available/sold.