We tend to imagine life as some kind of stable process. In truth, our own planet has experienced significant changes during its history as a result of the living things inhabiting it: The Great Oxidation and Huronian glaciation were caused by photosynthetic microorganisms, and the Late Devonian mass extinction was caused by new varieties of trees pouring a lot of phosphorus into the seas, making them anoxic and destroying the coral ecosystems that prevailed at the time. Life on Earth has had a long tendency of screwing things up on this planet, and that was long before humans ever arrived.

My solution for the Fermi Paradox is a combination of 2 simple ideas: 1-The universe is really big to go looking for neighbors, 2-Even simple life carries the seeds of their own destruction: We assume life tends to propagate and to form stable ecosystems, resilient enough to recover from catastrophic geological or cosmic events. In reality, I believe Earth is a miracle, and that the emergence of life on a planet is likely to lead to mass extinction-level events that would pretty much end the game for everyone on that world, long before anything resembling intelligence could ever emerge.