On that same FaceBook thread feed, Earl Reed is re-building a Casita
of a similar era he pulled from the weeds. The wood floor is completely gone. Thus, there is nothing to hold the thin egg shell to the frame. Once the floor rots out, it's a goner. The screws are likely all still in place. The screws don't necessarily fail, the floor does.
While very glad no one got hurt, I feel bad that these folk just purchased that Casita
, now wrecked. Unknowingly??? The wood floor was gone and this is the result. That Casita
has a fiberglass bottom is nice, but the vulnerable floor is the ONLY thing that allows the screws/bolts to capture the shell and pin it to the frame.