True up to the point where organized crime or racketeering intercedes. Teacher's unions are perpetually fucked but the Teamsters generally get what they want. In my industry, nobody gives the first fuck about the Writer's Guild (protip: if you're in a "guild" you are a thing of the past) but fuck with the camera union and you'll never work again.
My union president was venal, corrupt and incompetent. But he lasted fifteen years before crossing a more venal and corrupt (but more competent) union - the Louisiana local.