MDTs have always been specialty items and have never made up a significant percentage of the RV market.
Most that I've seen have been in the carney business. If you are doing 50-75k miles per year towing massive 5th wheels, the long term durability may make sense. For a more typical full timer doing 10-20k/yr, it's more a neat toy and I'm betting most of the people buying them will continue to do so.
From what I've seen, they don't retain value significantly differently, they still need trailer brakes and modern pickups are darn comfortable to ride in.
