So are you just asking whether this is what causes crime? If so, that's a huge argument. There are generally two sides to this.
Liberals tend to argue that people commit crimes largely for the reasons you gave. They say that people commit crimes out of desperation because they don't have the opportunity to make a good living in a legal way.
Conservatives tend to argue that people commit crimes out of choice. People commit crimes essentially because they are bad people and/or because the punishments don't scare them enough.
No one really KNOWS why people commit crimes, but these are two major theories.
If the person who cannot or does not have the money has an accentuated level of greed it is criminally proven that he or she is more likely to commit a crime than if the person just accepts the circumstances passively.
These days especially the ease at which a criminal can do identity theft and other cheap tricks of the sort makes theft a much easier task, and the temptation becomes higher. It all boils down to the level of greed of the individual which works as the motivating force that enables the unhibited nature of this behavior.
people who steal or kill for money are not necessarily the poorest of the people. People who steal or acquire money by other illegal and dishonest means include very rich people. Some of the biggest criminals engage in organised crime and are very rich. Therefore, it is quite clear that lack of money is not the primary cause for stealing or dishonesty.
I believe that the most important contributors to stealing are greed, desire to make quick money, inability to appreciate the long-term consequences of stealing, and a value system that does not perceive stealing as something wrong or undesirable.
Greed plays a large factor, but necessity can as well. There are many reasons behind someone commiting a crime, and necessity is a big reason.