Another point to consider is that many kids do not take their academics seriously during their young age. However, when they mature, their personality transforms completely. Furthermore, some students take interest in other fields like sports, art, music etc. Hence, they do not focus on their studies well. Lastly, I personally believe that there are a good proportion of people who do not like to simply cram for their exams. They become successful because of their creativity and their desire to do something different.