Instead...they succeeded in their stated goals, bringing happiness and prosperity to all?
At least in the case of Stalinist Russia, happiness wasn't the goal. The incredibly rapid industrialization of Russia was and that was a tremendous success though at a horrible human cost. It's no secret that non-democratic states are much more efficient than democratic ones.
Never ask two questions in a business letter. The reply will discuss the one you are least interested, and say nothing about the other.