Yes, you don't have to look hard to find examples of government projects that are plagued by agency problems, incompetence, and grift. However, those exact same things play out in the private sector. They're problems endemic in /any/ large undertaking.
You feel it's worse in the public sector. I feel it's just as bad in the private sector (just that it's reported much, much less). You've worked in both sectors, I've also worked in both. Only way to tell which of us is right is some sort of serious, objective research. My stance is that newspapers and other popular media are just noise, especially since government waste is such a easy go-to narrative (a good example being the "$20,000 hammer").