Hitler is an extreme example of what an autocracy can look like, but most autocratic regimes do not look like this. Successful autocracies in history include "the Roman Empire under Augustus... France under Napoleon, The kings and queens of England"
, and many others. The "Hitler" argument hardly holds water when it is an exception, and not the rule.
Autocracies are more efficient than democracies, both in economics and in enacting laws and policies that serve the greater good.
In a democracy, because the power is spread across so many people, debate becomes endless and the government becomes stuck in a rut of deliberation in which nothing ever gets done. Putting all of the power into one central leadership ensures snap decisions, which means faster solutions to society's problems.