Is the theory that if the box isn't opened, it doesn't depreciate?
From my experience, it's more the rule of offer vs.demand, which dictates the price tag. It has nothing to do with the original price.
In the case of a TAM, it's definitely very very very rare.
At the end of the day, gotta find the buyer ! Look at the Pixar NeXt Cube listed in a previous thread. First asking price was $25k. Now it's down to $7k.
However, there is a big gap between a brand new retro Apple product sealed and unsealed.
It's always magic when you open the package for the first time, knowing it was sleeping "untouched" for all these years. Happened to me with several Newton and an original iPod.