You live in a fantasy world in which countries with completely different cultural legacies and histories can automatically become republican in spirit and capitalist.
There is a reason that North Korea is still a totalitarian dictatorship and that South Korea, which started off with 'strong man' dictators, is now a prosperous democratic nation.
It takes time to build those institutions and often the choice is ONLY communism or some other socialist strain vs. right-wing strong man state. You build up capitalism and a strong middle class and you progress towards democracy.
It's like Vietnam. Even a 'stronger' and more stable South Vietnamese government could never have been a TRUE democracy. Because the institutions had not been fully developed. But they WILL NEVER BE DEVELOPED (within a life time) without holding off the Marxists.
I would make the argument that a Constitutional Republic (the Founders did not establish a Democracy in the US, for good reasons), is only stable if the majority of voters are property-owning members of the middle class. If the voting majority are the uneducated poor, then elections turn into contests between competing bands of looters.
South Korea is a reasonably stable republic because it now has a large middle class. Zimbabwe is a starving basket case because the voting majority put looters into office