"Life, plus 1000 years" is a useful mindset for judging our nation's policies. Do they serve not only the living but also all those who will live over the next 1000 years? Otherwise, what are we sentencing future humanity to endure?
In jurisprudence, multiple life sentences are handed out to mere mortals because there's a tendency for convicts to come up for parole early in their sentences. A judge leaves a margin for error, exagerating a sentence, knowing it could shrink. When considering our collective impact on the future, the tendency of many is to conveniently discount it, to minimize or dismiss altogether, to assume everything will work out. This is a perilous path, given that consequences could be far greater and come much sooner than expected.
The future is unprotected by any of civilization's institutions. Future people have no legal standing, (although, interestingly, a landowner's right to future profit does). Financial markets suffer from a severe case of near-sightedness. Government is under siege around the world. We punish criminals as if they will live forever, yet talk, or don't talk, about the future of civilization as if it has none.