There are many reasons why people steal. need, greed, anger, opportunity. I saw a social experiment video where a bag of goods was left in a Home Depot parking lot like someone forgot it and left it behind. Some people returned it to the store and some people just snatched it up. Three minutes before they had no intention of stealing, but presented with the opportunity they took the bag of goods.
Those are the people who are extrinsically motivated. They don't have a proper sense of right and wrong, hence they require laws and the fear of consequence to make them behave like decent people. They had no intention of stealing before because the risks were too high. Once the risks were low, they took the opportunity. These people are also why, IMO, religion was invented.
The people who returned the goods are intrinsically motivated. They have an inherent sense of right and wrong, and will do things because it's for the betterment of others and society. If you see someone returning a shopping cart, as one example, chances are they are this type of person.
It's hard to say what proportion of society is one or the other. And it's not a black and white line, either. For instance, someone who is intrinsically motivated may act poorly if they are desperate.