It starts with Spanish and French colonialism.
Haiti
The Duvalier dynasty which ruined the country. He had a poor relationship with the US. The US was sending millions of dollars of aid to Haiti (in 1950s dollars) at the time, Duvalier stole it, so we stopped sending aid which was just making life worse for them. This is one of those cases where it really isn’t the fault of the US.
Avril was an ally of Duvalier.
Abraham was a military officer under Duvalier.
Aristide was overthrown in a coup by Duvalier supporters.
The US overthrew that dictatorship. https://en.wikipedia.org/wiki/Operation_Uphold_Democracy
His successor Martelly then worked hard to traffic cocaine to the US and Canada. He has been sanctioned by Canada. His country needs reform and all he did was work to be a drug kingpin and enrich himself.
Things were finally turning around when Rene Preval was President and then the earthquake fucked everything up. His successors have used the country as their personal piggy bank, and there has not been any major reform effort to deal with the endemic problems which keep Haiti poor.
The 2010s saw slow growth and then COVID made things worse again.
Corruption in Haiti is endemic, and it’s hard to spin the economy up when hurricanes, earthquakes, and tsunamis aren’t slamming them. https://en.wikipedia.org/wiki/Corruption_in_Haiti
Every single one of these people are native born Haitians. Haiti hasn’t had an election since 2016.
Dominican Republic
We can compare to the Dominican Republic which was occupied by the United States from 1916-1924.
Back in the 1980s the Dominican Republic and Haiti started at the same spot under military dictatorships.
The Dominican Republic on the other hand after removing Balaguer out of office in 1996 has had reliable elections and stable growth leading them to be one of the best places to live in the Caribbean. They focused on building a strong economic system, rooting out corruption, and building macroeconomic stability.
Today, the Dominican Republic has a significantly better GDP per capita, longevity, and overall quality of life, but with the exact same geographic challenges.
The Dominican Republic scores 35 , on par with Ukraine and Bosnia and Herzegovina, so not great, not terrible. Haiti scores 17 next to North Korea and Nicaragua. https://en.wikipedia.org/wiki/Corruption_Perceptions_Index
The Dominican Republic has a GDP per capita 7x that of Haiti today, and Dominicans live a decade longer than Haitians. Haiti is a tragedy.
But the Dominican Republic goes to prove Haiti did not have to be this way.
Things can change.
It starts with building a good quality of government and a high trust society.