This is a very old argument against democracy. It's also divisive in the sense that you have the "competent" folks on one side and the "incompetent" ones on the other. Who decides who is "competent" to vote? About a century ago it was believed that women were not competent to vote. Before then it was thought that people who didn't own land couldn't possibly be responsible enough to vote. Also, there is no such thing as an objectively "best leader". That way lies tyranny and ruin.

Democracy isn't about voting for candidates anyway. In general it's about having some say in decisions which affect your life, and as such I think it's still more of an aspiration than a reality.