The value of a copyright isn't really part of the equation though (I know this is orthogonal to your point). From the Constitution (emphasis mine):
"[Congress shall have the power] to promote the Progress of Science and the useful Arts, by securing for limited Times to Authors and Inventors the exclusive Right to their respective Writings and Discoveries."
Further, from Fox Film v. Doyal (again, emphasis mine):
"The sole interest of the United States and the primary object in conferring the [copyright] monopoly lie in the general benefits derived by the public from the labors of authors."
Copyright terms come down to a simple metric: if the public would benefit more from a work being in the public domain, the work shouldn't be copyright (insofar that the progress of science and innovation is not stifled). Corporations and anyone making a living off intellectual property have nothing to do with it; copyright exist only for the benefit of the general public. And with some of the most innovative systems software of the last decade being developed for free, you're going to have a hard time arguing that such lengthy copyright terms are needed to ensure that innovation happens. Linux is billion dollar project that happened organically; I just don't buy it that ~100 year copyright terms are necessary.
"[Congress shall have the power] to promote the Progress of Science and the useful Arts, by securing for limited Times to Authors and Inventors the exclusive Right to their respective Writings and Discoveries."
Further, from Fox Film v. Doyal (again, emphasis mine):
"The sole interest of the United States and the primary object in conferring the [copyright] monopoly lie in the general benefits derived by the public from the labors of authors."
Copyright terms come down to a simple metric: if the public would benefit more from a work being in the public domain, the work shouldn't be copyright (insofar that the progress of science and innovation is not stifled). Corporations and anyone making a living off intellectual property have nothing to do with it; copyright exist only for the benefit of the general public. And with some of the most innovative systems software of the last decade being developed for free, you're going to have a hard time arguing that such lengthy copyright terms are needed to ensure that innovation happens. Linux is billion dollar project that happened organically; I just don't buy it that ~100 year copyright terms are necessary.