you cannot possibly be postulating that profitable activities can never be considered useful, are you?
And public institutions may serve a useful function, but again seem to be mostly about civil service powerbroking and providing extremely safe employment.
There are certainly (often larger) nonprofits with a tendency of overpaying their leadership and/or pushing policies favored by their corporate funders. I would in this context however not conflate "most visible" (ie largest advertising budgets) with "most". Most nonprofits I have worked with are ran and operated by hardworking people on minimal budgets.