The general perception is that wealthy people are charitable because they can afford to be.  Let me propose another possible cause effect relationship between wealth and charity.  It may be that people who have the instinct to help others without thinking about themselves first are in the margin more likely to accumulate assets.  So that it is not only that some people are poor so they can’t be charitable.  Some people are not charitable and as a result they are poor.

It is not always true of course.  There are plenty of examples of greedy bastards who accumulated lots of wealth and they don’t have a charitable bone in their bodies.  But it is not the only way that people accrue wealth.