Put the best five guys in the NBA together on one team and put them on the court. You'll see brilliant plays by one player at a time, but they won't play to their peak potential because they're not used to playing with each other as a team. They are not familiar with each others' instincts. They are not used to working together.
Take the guys ranked 25 through 30 and let them train for a month, practice, and get used to each other. Then put them up on the court against the top five guys. They'll win. Why?
Because 25 through 30 is six people.