What would happen if every spare copy of At Ease was heaped into a pile and burned?
Would piracy of At Ease then be acceptable?
That depends. Was this burning a decision by the copyright holder? Or was a manical Steve Jobs (i.e. not the copyright holder) trying to destroy all evidence of Apple products prior to NeXT OS X?
It's been said before: copyright is about more than financial gain. Copyright owners may have legitimate or personal reasons for wanting something destroyed.
Copyright law does not make exceptions for individual acts of piracy that are done for some distorted notion of preservation(1). If you want to do that, then chances are that noone is going to stop you. Yet, when you do so, you should still ask yourself if it is important enough to you to risk prosecution for copyright infringement.
If it is important enough to risk prosecution, and you do preserve the software, maybe one day you'll even be regarded as a hero for being the only guy on Earth to preserve a copy of AtEase. Or maybe not.
(1) I would argue that preservation is only relevant if you can preserve the bits and documentation at a minimum. Preserving the original packaging, media, documentation, and advertising literature is an even better act of preservation.