Because they'd go to jail you idiot for armed robbery.Why would anyone risk their lives protecting some rich asshole, when you could just turn around and rob your boss instead?
When it comes down to it, society runs on a sort of honor system, as long as I believe that everyone around me is respectful of norms and institutions and will act in good faith, then I am willing to do the same. Once people start losing confidence in the system, then society starts to crumble and it's difficult to build it back up again. In modern times, it's certainly not the poor who are trying to undermine societal stability, it's the rich who continually try to grab a bigger piece of the pie for themselves while proclaiming that social harmony and sharing are evil. And while they make themselves momentarily better off, weakening the institutions that allowed them to accumulate this wealth in the first place is going to hurt them in the long run, whether there is a violent revolution or just a long and slow process of decay and rot.