I hear what you're saying here, but one of the ways we've been able to successfully preserve software was because, even though folks weren't supposed to keep this stuff around, they did anyway. Business goals rarely align with preservation efforts. While I do know that Microsoft does keep a vault of old software, production materials, etc (I believe they even have a position on staff for a Librarian, or at least they used to), for many other positions, that simply does not exist.
Can we please stop with the mental gymnastics? Taking something without permission that doesn't belong to you is stealing. It may be justified stealing but it's still stealing.
Monks used to write books out by hand. If you were to go to a monastery, and copy a book line by line, you will have taken nothing at all. Nothing will be lost.
It's not taking, it's not stealing. It's just making a copy. You are the one doing gymnastics.
You're taking something that doesn't belong to you and copying it. It's stealing. In order to even make the "unauthorized copy" you mention, you have to take the thing first. That's the stealing.