It's primarily driven by wealth inequality, not poverty. Who is someone going to steal from in Mississippi? Their also-poor neighbor who's got nothing worth stealing? The median income is around $25k in that state.
If your society is full of thieves, what do you do to address it? HINT: the French Monarchy tried solving the problem via tightened enforcement.
Ultimately though, you have to change the culture. Make thieves seem pathetic and mean rather than rebellious and cool.