Per my other reply, if you accept the original terms of the Fermi paradox, which is that there should be a lot of alien civilizations, then merely killing off "nearly all" of them is insufficient. It only takes one species to colonize the galaxy. Life is probably nearly impossible, but it only takes one cell to colonize a planet.
Per my other reply, if you accept the original terms of the Fermi paradox, which is that there should be a lot of alien civilizations, then merely killing off "nearly all" of them is insufficient
Only up to certain values of "nearly." If you make intelligent life rare enough and suppress it from spreading out of its home system then you fulfill the original terms. My "Civilization Instability Hypothesis," combined with the indivisibility of the alternative could fulfill the original terms.
