It seems to have been pretty successful at its intended purpose: The equation was formulated in 1961 not for purposes of quantifying the number of civilization

It seems to have been pretty successful at its intended purpose: The equation was formulated in 1961 not for purposes of quantifying the number of civilizations, but as a way to stimulate scientific dialogue at the first scientific meeting on the search for extraterrestrial intelligence (SETI) Even today, it’s not the end all be all tool but there are still serious papers being published that refer to it.