The same goes for anything that provides value right? If you make some useful software, by that logic I should be allowed to copy it and use it in whatever way I see fit (including commercially), no matter what license you used?
I can see it argued that, being less critical than medicine, perhaps a book or software could be "out of print" for longer than medicine being out of production before the copyright protection ceases, but ultimately the only reason we have copyright to begin with is too encourage people to create and make available.
So yes, by all means. Make orphaned and out of production works publicly available.
I do think that at some point that window is long enough that the author and publisher lose any logical justification for keeping something unavailable while the rest of us subsidize their ability (via courts, laws, and police) to do so. After all, if we're paying for that stuff, what are we getting in return?