No, it shouldn’t.

A Great Idea Lives Forever. Shouldn’t Its Copyright? – New York Times

The question “why is the duration of copyright limited?” is asked somewhat frequently in copyright circles. An editorial in yesterday’s Times argued [note, you may need to be a Times Select subscriber to view]:

Booksellers that publish their own titles benefit not from escaping the author’s copyright, but the previous publisher’s exercise of a grant of rights (limited, authors take note, to 35 years). “Freeing” a literary work into the public domain is less a public benefit than a transfer of wealth from the families of American writers to the executives and stockholders of various businesses who will continue to profit from, for example, “The Garden Party,” while the descendants of Katherine Mansfield will not.
[emphasis added]

While the author has a point that, like many other areas of copyright, profit from public domain works serves to enrich industries which are already financially stable, a crucial point is glossed over: future creative works depend on building on the shoulders of past work. Helperin is right that ideas are rightly beyond the scope of copyright, but in our modern “rip and mix” world the flexibility to use previously copyrighted expression (which has lapsed into the public domain) will likely be demanded by the public.

Or, if cultural arguments aren’t your preference, the copyright has historically been limited because of the potential for abuse by copyright owners. Since copyright in a work is usually transferred from creator to publisher anyway, one might ask Helperin “why favor the original ‘executives and stockholders of [a business]’ over another?” …especially when that subsequent publisher might reinvigorate the original work.

No good case exists for the inequality of real and intellectual property, because no good case can exist for treating with special disfavor the work of the spirit and the mind.

The author shouldn’t forget that intellectual property cannot be owned in any real or metaphysical sense. Copyright holders own a copyright– never an actual creative work.

…and in his typical innovative fashion, Lessig has created a wiki page for an organized rebuttal.