The Drake equation assumes there are no limits to technology and that without some kind of great filter the Universe would be so permeated with advanced civiliz

The Drake equation assumes there are no limits to technology and that without some kind of great filter the Universe would be so permeated with advanced civilizations that signs of their existence is inescapable. I find it more likely that the speed of light is the great filter and that interstellar travel is so difficult that the rare instances of life are unlikely to leave their star system never mind their galaxy group (which would require faster-than-light travel).