I believe you are mistaking the cause for the effect. Dumb down the electorate, and you have to dumb down the candidates through a process of political Darwinism. If an honest conscientious candidate is presenting well-reasoned honest positions to this electorate, they look at him like a hog looking at a wrist-watch. Meanwhile his opponent says, "I'll make you happy. I will give you bread and circuses." The electorate examine the two, and elect the latter. Politicians learn from this, that being honest with the electorate means defeat, while giving them outrageous fantasies wins.