This is why politics and the political system interests and frustrates me in equal measure. And if we're being honest, it will never change. Power corrupts and all that. Are there decent politicians out there? Of course. However there are also a significant number of career politicians that talk a good game but often know diddly squat about anything other than trying to progress their careers and those of their buddies.
I liken it to the workplace. Those that talk a good game are often the ones that climb the career ladder to senior management level. However, many (although not all) of them aren't actually that great at management or leadership, relying heavily on those around them and the lower ranks.
Call me a pessimist but things like this (the OPs point) will forever be an issue. As I touched on, power and greed corrupts, it has always been thus and will always be so. If anyone thinks otherwise they're deluded.