So, what is your explanation?
Their independence was not organized like the U.S.. Haiti was at best a sugarcane factory for France, and not a society of “citizens” rising in revolt over red tape issues.
They managed to win, but had no guiding pro to fall back on. The U.S. refused to recognize the place, and trading with the Spanish Empire was not happening because it would legitimize a slave uprising.
Haiti made a haphazard shot at governance the best they knew how. Even splitting into a republic and kingdom for a period.
But they were just screwed from the start. Add to that multiple U.S. interventions, and business deals, corrupt leaders, natural disasters, and you have a pepetual dirt poor nation surrounded by far better off nations that arent THAT different in terms of their resource wealth.