In general, any time you can walk into a dealer and buy a brand new product (with financing and no wait), people will be less likely to pay a higher price for a late model used unit. My observation is that
Bigfoot, which also sells through dealers, seems to follow a similar pattern, though it may be less pronounced because the dealer network is so small compared to Airstream.
It can also be difficult to gauge true retained value for dealer-sold makes because actual transaction prices vary and are not public information.
The factory-direct sales model does seem to support higher resale values because the lack of discounting and long wait times for new trailers mean people are more willing to pay a premium for a late-model used unit.
I don't know about the target demographic for the Nest- it will be interesting to see. Barely a week after they went on sale I saw one on the interstate pulled by an Audi Q5. Couldn't see who was in the vehicle.