Most people shop lift for the (thrill) of not having to pay for something. People want to spend money on things that they want to spend it on. It's very common for shoplifters who get caught to offer to pay for merchandise. Very few people steal food to live on.
Kleptomania is the inability to refrain from the urge to steal items for reasons other than personal use or financial gain. For some people stealing is like an addiction. It has nothing to do with wealth or lack of wealth.