In any team, you need strong cohesion between the players, instead of individual talent and dependency. From basketball's point guards yelling out the plays, to the quarterback in football who is responsible for the moves made on the field, they all require teamwork. It is the same for volleyball. Without a strong on the court relationship between the six players, you will not have a winning team. .
The key to having a winning volleyball team is the ability for all of the players on the court to be able to work together and play defense. You may have a strong offense with three players in the front row who can spike a ball on the other player's face, but you have to have a defense that can keep the ball up and be able to set up a good hit for the hitter. The only way to have an offense if to have a defense. .
The opponent serves the ball over, usually to the back row. Each of the three back row players have to communicate, either by voice or by body movement, whether or not they"re going to get the ball or if it's someone else's task. If they don't communicate the ball could end up falling right in between the players without anyone attempting to pass it. Once someone passes the serve to the setter, he must be able to set up a good hitter that will surprise the other team's defense. If you can hit the ball over but the defense picks it up, you must jump right into defense. The setter on the other team sets it to the right side. The middle then shifts over to the left side to block the hitter. If the blockers block the hit, then it's right back to defense. But if the ball comes over, one person from the back row moves forward to pick up the "dink", the other two back rows stay back for the deep, and right front row moves closer to the middle to pick up a dink on the right side.
A strong defense depends on the front row, and if the front row fails, the back row picks up the slack, keeping the ball up as one cohesive unit, instead of a single individual doing all of the work.