Louisiana has one of the lowest average incomes in the US, one of the lowest household incomes, and one of the highest income inequalities. And that isn't even talking about income inequality by sex or race, the crime rate, government corruption, etc.
What happened in the last 200 years to cause this massive of a drop off?
Edit: I just realized the title should say "crown jewels" and now I feel kind of stupid
First, we are talking two hundred years, and Louisiana had a very different shape when it was French : US history basically happened between now and then. Second, is it Louisiana, or is it the Southern states that are poor and unequal ? Look how similar its neighbours are in the two indicators you mentioned. It's proably part of a broader southern dynamic and history. And third, barely ten years ago, Louisiana was hit by the cotliest hurricane in History. Needless to say, it's hard to recover from that type of horror.
From my understanding, Louisiana was only mostly valuable to the French when they had the nearby ports of Haiti to supply it. After the Haitian Revolution, the French Empire had no nearby major ports to handle goods going in and out of Louisiana, and thus it's usefulness deteriorated.