Licenses are also used to extend the owner's right over the software and how it is used. Most people don't read the license agreements and that's what is profitable for companies. For example, did you know that if you send a file to someone over MSN Messenger, Microsoft reserves the right to claim that software as his own? It's all right there in the EULA.
They are not always legally binding. If they contradict with the law then the law comes first.