I'm sorry, but once in a while I have to pop in and do a reality check.
Are you in the film business? Do you realize what it costs to build these full-scale replicas for movies? Do you understand that once a film is done the first thing a studio wants to do is CLEAR the set so they can prepare for the next film?
Like automotive plants, studios are factories and the last thing they want to do is be idle. They want to use available space as quickly and as efficiently as possible.
The full-size Falcon was not built to be a permanent structure. It was fabricated and built as quickly as possible to be used in films and was never meant to last forever. That's the case for 99% of the props, full-scale vehicles, and miniatures that are ever built for movies.
It's only been recent decades where people have realized that there might be a secondary market for reselling of production movie memorabilia -- particularly for science fiction film and TV series which still get treated as stepchildren.
Another thing is that when Jedi was finished filming, LucasFilm was getting deep into production with Indiana Jones and the Temple of Doom. LFL was big back then, but not as a big as it is today and had to commit its resources to the next film it was producing and the films beyond that. I think saving a huge prop that would have to be shipped practically halfway around the world was the least of its worries!
Considering the sets and full-scale vehicles that had to be built for the Original Trilogy is it any wonder that LFL wants to use CGI as much as possible now? Granted, CGI doesn't always come off as well as "building the REAL thing" but there's a heck of a lot that has to be struck and scrapped once a film is finished shooting...(!)