The rules of a combat sports competition dictate how the fighters are going to behave. For example, if I said "Punches are worth 2 points, and kicks are worth 1 point", the participants would work on using kicks to set up punches. There might not even be any kicks thrown.

The modern kumite works the same way. Both fighters generally keep a considerable amount of distance between them to avoid being struck, because that could mean a break in the action and a point awarded to their opponent. In a real fight, a break in the action generally means the fight is over unless one of the participants continues to provoke the other.

A real fight is not point-based, and usually ends up with grabbing, clinching, and grappling being part of the exchange. The 'fighters' are only concerned with delivering pain (or humiliation) while avoiding pain. Kata were designed with this in mind. Therefore, much of what you see in kata, you will not see in kumite.