There is one more explanation of why we are “alone” in the visible “Universe”. It may be because we all live in a simulation. We may only speculate on the goals of the simulation, how fine-grained it is, is it individual-centered or world-centered in it’s model, or even if it is a model of creators of the simulation, etc: Then it is more logical we are modeled here alone, in this Petri dish. And in my mind Fermi paradox, Case IV or Fact A are at the same level as the simulation argument or God created the world belief. In such existential questions Occam’s Razor is as useful as statistics for Thanksgiving day turkey.