1. The ones I have been in have been in rural communities on acreage. People sacrificed the quality of their home for the purchase of these long, rectangular 10 acre lots. Many of the lots these are on are just chock full of scrub brush, junk trees, and critters (biggest spiders I've ever seen!). Some of these lots have flooding problems at times, and not all of the areas leading to these lots are on paved roads.
2. The ones I have toured have not been well maintained by their owners. People don't appear to treat these like homes that they value. That lack of care shows (and smells) over time. It makes them super hard to sell.
My vote is that they DEPRECIATE in our area. In many cases, it's cheaper to buy new.
However, there is a Jim Walters home sitting on my Grandfather's land near the Natchez Trace in Tennessee. My cousin lives in that home with his family, amid a forest of mature trees and streams. Because of the family history and the location of that home, it is priceless as far as I'm concerned. So, beauty is in the eye of the beholder and value is in what a buyer will pay for something!
Have a blessed day!