Many of those countries (though not Haiti) are very young; they only seem viable (at least economically) when they have strongmen in power (even Haiti’s tourism did well under the Duvaliers).
When you have one thief in power, he has an incentive for the country to be prosperous, so that there is more to steal. He also has an incentive to suppress minor thieves, because they steal from HIS supply of loot.
When you have thousands of thieves (bureaucrats, warlords, whatever you call them), their incentive is to steal what they can before some other thief steals it, with the result that they wreck the system that produces the wealth they steal.