This is off topic - but I honestly feel that the solution to most issues in this area could be solved easily by massive change to copyright law; a way to make everyone happy.Things go out of print all the time. Keeping works available perpetually is a very recent development in the world of publishing. Our feeling of entitlement to old works is not yet supported by history.
This has been something I've been thinking about a long time - and I will note I am biased as I have been raised during the internet era and there isn't a high likelihood I will publish a book. But I've always thought that having a right to exclusively make money my entire life off a work is too much - and my estate or publisher having the ability to make money exclusively off my work for way, way after I pass away is pure insanity.
I don't know what a fair timelimit is, especially in today's age where it is possible (though not guranteed) to be able to interact with any past work as long as it's online.
But if I ever publish something, and if I were to publish something now... I think after 20 or 25 years, when I'm hopefully still around but now towards my middle age... I think that'd be enough time to have sole rights to earn money to my work. At that stage, I would hope I'd be like now, and have nothing but pride to see others enhance, remix and change my work, and not have a damn say in it.
... then again, I believe pretty much all software should be open source, and that is the area I work in, so I'm already a bit off kilter.