A world were only intelligent people were bred would be a very horrible world in the long run. Imagine a world where everyone was inclined to go to college to learn higher end jobs, and had the potential for better social understanding. With everyone wanting the better jobs, who would be the farmers, the mechanics, or the department store cashiers? Intelligent people wouldn't want these jobs, yet they still need done. Now imagine if the government came up with a system to fill these jobs, whether it be by lottery, chosen by birth, or any other means. The person chosen would not be happy with their life.