Until you take into consideration the Fermi Paradox and "Great Barriers". Our planet is about to be inhospitable to life and there's nothing we can do about it. We've been on the verge of nuclear annihilation on a few occasions, including now. It's getting easier and easier for one person to destroy the Earth, so it's a matter of time before it happens. Assuming we're a typical progression of technology, then it would stand to reason that any species who scrapes and claws their way past extinction event after extinction event to develop sentience is almost certain to destroy themselves as soon as they are able.