Your experience, though, does not meet the reality that there are many fine non-profit success stories. There are a lot of non-functional ones, but I think all folks are pointing out is that it isn't as dire as you have seen.
Success is not the same as functional. One could argue that wikimedia has been very successful in its mission and it is at the same time also disfunctional.
I wouldn't call any of the non-profits I've worked at failures.
Hell, many people have described companies like Microsoft as badly disfunctional, but it would be hard to argue that they are not successful.
If I stepped on anyone's toes with my post, I apologize. I was not trying to take a swipe at any one or any type of organization. I'm still involved with a number of organizations and admire and respect the work that they do.