“The economic effect of this 20-year extension – the longest blanket extension since the Nation’s founding is to make the copyright term not limited, but virtually perpetual. Its primary legal effect is to grant the extended term not to authors, but to their heirs, estates, or corporate successors. And most importantly, its practical effect is not to promote, but to inhibit, the progress of ‘Science’ by
which word the Framers meant learning or knowledge.”