We always took the term "Museum" to be an example from the time frame. Like a 2 thousand year old pot from Egypt. It's displayed as it existed in the time period. Not restored with modern materials to look brand now. We got a lot of flack for having poor conversion games. But that is what a game looks like when it hits the end of it's useful life and the next stop is the dumpster, or Deer Hunter. This was the life cycle of many, many games.
Now if we had a better example of a game we could display in storage, we would display it. But we didn't reject a well used game as that is what many of us played in the back rooms of the mall. That is the experience we got.
This is also why we never put an LCD or a 19 in 1 in anything. If we had the time, and the CRT to do it, we would pull the LCD out. The exception would be a Pi replacing a LaserDisc player, because the game did need to be playable. (I think we had 1 to 2 in some games, the rest we keep the LD player going if we could.)
Sadly, the pubic seems to think that museum is the same as mint. I am not sure I can come up with a better word to describe what the MOP is then museum. Collection of Pinball does not have the same ring.