We bought ours and it had set for at least 5 years from the date of the safety sticker and some other papers I found, that took quite a toll on it. I think what happened with it was the folks that owned it were in construction. Well we know what happened during the recession, I think they likely couldn't afford it and let it set and must have finally sold it. I'm guessing it was under covered storage for part of that but likely during part was not. They could have gotten more out of it if it had been cared for but like you say people do funny things. At least they finally sold it.
I don't plan letting it set if I quit using it, but it is old and I doubt someone else will spend what is required to keep an old one going. I would hope so as we have repaired and updated it. I need to do some cosmetics inside also. Just hope someone eventually takes the old girl and continues with her when I'm done. I too hate to see things like this just allowed to rot down.