The problem is that politicians are good at getting elected, but nothing else. Which means the people who know least about the things they govern, govern. It's a flawed system, unfortunately.
The issue is massively exacerbated in countries with no upper limit of campaign spending or air time. Ideally, all candidates should get an equal, small amount of air time and a very limited election budget. The more their policies and qualifications do the talking the better, and the more they do the talking, the worse.