The first perspective shift is to step back in time, and realize the universe is very young. With 20 trillion years of star generation ahead, the universe has only covered 13.7 billion years or roughly .07% of its life span. Compare this to a person who expects to live 70 years, and you’d get .07% * 70 years = roughly 18 days. So in human terms the universe is a three week old baby. No wonder there’s not too much life out there yet.
Utterly fascinating exposition on the probability of existence of extraterrestrial life in our galaxy and universe. In a nutshell, in “universe years”, our much beloved universe is still in it’s nappies. It takes time and luck, heaps of both, for intelligent life forms to evolve and attain technological competence levels sufficient to establish interstellar and intergalactic communication before blowing themselves up. Consider ourselves. For all our technological prowess, we’ve just barely begun interplanetary exploration in our own solar system let alone galaxy! It has taken us at least 4 billion years to get thus far and we have fallen and stumbled many times along the way. A single wrong turn and our technological civilization may never have been. To answer the question “Why ET isn’t here yet?”, give him/her time. And wish them luck. We’re like blind men on different continents trying to find each other with a torch.