"While some leaders in government, sports, industry, and other areas attribute their success to a well-developed sense of competition, a society can better prepare its young people for leadership by instilling in them a sense of cooperation."

Response:
A sense of cooperation can be one of the ways to prepare young people for leadership in government, industry, or other fields, but a sense of competition can be more conducive if done in a healthy manner for a lot of reasons.
A healthy competition means people should think of doing better than their peers, and taking the defeat in a positive way to analyse what the other person did better and what they can learn from it and improve themselves. But is certainly does not mean that one should look for means to degrade the other person instead of improving themselves.
A sense of such kind of competition helps people improve quickly as compared to when they are learning in a cooperative environment. For example, during university admissions, the environment is more of competitive than cooperative and hence helps bring out the best in the students.
Another example is that, 2 different political parties are inclined to work more efficiently when there is completion rather than when they are working together. Since they need to prove themselves better than the other one to maintain their position.
A cooperative environment is beneficial to an extent, since although it helps people improve, but it does so at a much slower rate, but, a sense of competition goes a long way since it encourages people to give their best.
So in conclusion, a sense of competition, a healthy one, where one tries to work on improving themselves rather than trying to degrade others, proves to be a better way to prepare young people rather than a sense of cooperation.