The survey seems reasonable. If you group the destination trailers and park models into a single group of RVs that don't move from their site, that number would be comparable to Pop-ups, a-frame, and truck campers. I don't mean to say that this would be a huge segment of FRF.
In the campground that we are in and other campgrounds near ours, there is also a good segment of 5th wheel campers that are being used as full time destination campers or mostly destination RVs. Owners of these units get a lot of use out of their 5th wheels. Additionally, if you are paying for storage of your 5th wheel, why not just park the 5th wheel on a spot within driving distance that you enjoy instead of at a local storage lot. For some, this really makes the 5th wheel experience a great value.