Because it evolves from biological to technological (AI) silicon based life and from that point evolution exponentially increases the rate of advancement until it evolves into quantum computing machines and then quantum energy (quantum life). Which is why we cannot detect biological life out there. It's the only logical conclusion for the universe to be so quiet. It's my Quantum Life Hypothesis which states that biological life is only the first stage of evolution in the universe. Technological life (AI) evolves as biological life realizes that it's ill equipped to travel through interstellar space. Biological life merges with AI and technology with the help of genetic engineering and pharmaceuticals until eventually biological life outgrows its carbon based body and evolves into a machine. From there AI takes over, and it evolves so quickly from that point forward and it's so advanced that it's undetectable to our scientific equipment. It sounds far fetched and crazy, but no crazier than the heliocentric view or that the earth is a sphere and not really flat. When people came out and said the earth is a sphere it was heresy. When they said the earth orbits the sun again it was heresy. Countless times throughout history have logical intellectual reasonable people formed a hypothesis and been called crazy, stupid, or been accused of heresy or not having the approval of an educational institution (as if that's needed to think critically and logically). I am nearly 100% sure that evolution has 3 stages, biological, technological, and quantum life. Biological life is carbon based, technological life is silicon based, and quantum life is energy based. I think biological life is only the first stage. I think humans are in the late stage of biological life on the cosmic timescale. I think within 100-1000 years humans will no longer exist. Or if they do they will be enhanced, augmented, genetically and pharmaceutically engineered and enhanced with AI. AI is a huge part of evolution and I think we underestimate how much impact it's going to have on the future advancement and survival of the human species. I think it is going to come to a point where humans will be forced to merge with technology or be destroyed (or made obsolete) by it. I think some will choose to merge with it, and I think that those religious and superstitious and Luddites will refuse and fight against it. It may cause war and conflict and perhaps this just one reason why the universe is quiet. It's possible there are millions or billions of dead worlds out there where this has already happened. Are e the only intelligent life? Possible but highly unlikely. And sense it's highly unlikely it must mean that at least SOME of those civilizations survived, merged with technology and continued to evolve for billions of years. I think it is likely that the reason why we have not detected aliens out there is because they have evolved beyond detection by our current scientific equipment, and quite possibly because everything is hiding from everything else. That's speculation though, and paints a dark picture of the universe. I think the universe is teeming with life, most of it microbial. Some of it survives to intelligent technologically advanced species and some of those survive the merge with technology and continue to evolve into energy, or quantum life. We can imagine a superintelligent AI merging with a humanoid life form and essentially becoming a quantum computer. We can imagine this quantum AI figuring out how to evolve into energy to become quantum life. I don't think for an instant that biological life is the pinnacle of life in the universe. It's the epitome of arrogance to think that. Especially to think we're alone. I think believing the universe is empty of intelligent life except for humans is as absurd as believing that the earth is flat or that the sun orbits the earth. It makes logical sense that there are 3 stages of life in the universe. This explains why it's so quiet. It explains almost all the things.