Even if someone derived material satisfaction from a theft and never provided restitution for the crime, you might think that person would be happier or better for it. Not so. Material satisfaction is only one aspect of happiness. Self-esteem is also a component of happiness. A major factor of self-esteem is self-reliance. So long as a person gains material values from the productivity of others, his or her self-esteem will suffer and, consequently, so will his or her happiness.
That is not to say trade is immoral. A person who can produce values that others desire is living independently in the sense that person is consuming only what others have consensually agreed he or she earns.
Since productivity is a necessary component for life, thiefs who willfully refuse to provide restitution for their crimes despite an ability to do so understand that they are able but not willing to survive on their own. At a fundamental level, they know they are not worthy of the life they have. These (for lack of a better word) spiritual values mostly pertain to consciousness, and so they contribute to one’s reasoning ability in the immediate and long term.
The mistake often made when examining the consequences of an action like theft is to take a snapshot of time, as if that represents the full picture of the circumstance. I would not argue that a starving person who steals a loaf of bread is worse off. However, it does seem self-evident to me that the person would maintain a happier life by taking actions to be able to live independently so that he or she is in the position to compensate the original owner.