More expensive equipment is often re-used especially animatronics. There is a long history of "this use to be be that" in present day attractions. However, that is not always the case. I believe 3 of the Nautilus Subs from 20k survived to be reused elsewhere. The rest are in a landfill.are sets sometimes just re purposed and others just covered up?
It is also not uncommon for attractions and parts of attractions to be concealed behind walls until the space they occupy is needed. A good bit of Cranium Command still exists behind a wall in the old Wonders of Life pavilion.