Increased economic inequality is stopping the non-rich from giving to charity. This means charities become dependent on a few rich, and don't dare disagree with them.

This happens even more and faster when some rich person, such as Bill Gates, makes a special effort to gain influence over a field, such as education reform.

One charity which this is not happening to is the Free Software Foundation. In most years it gets only a small part of its income from corporations or big donations. That's not to say it would reject a large donation if you give one ;-}.