My theory to explain the Fermi Paradox is that the Earth experienced a critical periodicity and severity of cosmic and tectonic extinction events to lead evolution to high intelligence of mammals.
This required a location in the empty space between spiral arms so the incidence of high energy impacts and radiations from the Galaxy are minimized, and that our giant planets did a long sweep of the inner planetary orbits of space junk so the only asteroid belt left is far beyond the orbit of Mars; but left comets that refilled our water supply for 5 billion years.
It also required a dense, molten iron core producing a magnetic field that shields us form solar radiations, but periodically flips with a time of high radiation during the reversals.
The combined probability of these parameters are so low that it is reasonable to expect we are the most advanced civilization within reach by our current Physics theories.
Unfortunately, the Anthropocene is providing a perfect storm of unprecedented extinction affects, We are already in the top ten extinctions with the fastest transition short of a giant asteroid or volcanic eruption that caused years of darkness and cold.