I've only really been close to one (the owner of the small company i worked at started one), and in the past I did some consulting work for anther, but that describes what I saw in both situations fairly aptly. There seems to be a massive amount of power and ego wrapped up in the creation and running these things from my limited experience. If you were invited to a board, that's one thing, but it takes a lot of time and effort to start up a non-profit, and that's time and effort that could be spent towards some other existing non-profit usually, so I think it's relevant to consider why someone would opt for the much more complicated and harder route than just donating time and money to something else that helps in roughly the same way.