Sagan was so amazing in thought and generous spirit, and prophetic warning us as a species and as citizens of the universe, but he really missed (and I base this not just on this quote, but from other of his writing and videos I have read/heard) is that he thought too highly that humanity would succumb to the allure of superstition (astrology, horoscope, fortune telling, crystals, new age crap, etc.) and not the real danger of fundamentalism.
But, in his time, the danger of fundamentalism was not seen by many and its power, especially as seen in Dominionist ideology, particularly in TV and megachurch Christianity and many of our Republican politicians (Perry, Bachmann, Santorum, Gingrich, Akin, Ryan and Romney, etc.) was still pretty much relegated to the margins of society and was not the main player, and even Muslim fundamentalism was not seen as a particular danger beyond plane hijacking or violence contained to the Muslim countries.
But still, one wishes that Sagan would have seen better that astrology would not kill us - but fundamentalism will.