I tend to agree -- it seems to me that democracy creates ecological conditions favorable to long-term survival, because the risk of destruction under dictatorship is asymmetric with respect to the probability of prosperity.

Democratic checks-and-balances assume the inescapability of despotic buffoons who rise to power either through force or sometimes even through the people's choice (while it's good to believe in the wisdom of crowds, one must always account for its lapses). I think these are very realistic assumptions.