Any life form that can (a) divorce its intelligence from its physical substrate, and (b) forge a sustainable energy relationship with one or more stars, has the capacity to be very, very long-lived. I think if there exist aliens that we are capable of finding, they will be in the form of slow-moving, slow-spreading "Space Ents", beings who are perfectly content to send SYN/ACK messages with 500,000 year ping times. Play out natural selection in the ginormous sandbox that is Universe, and I think that's the only inevitable outcome (barring FTL).