I disagree. When it comes to the defense of your life, it is precisely the rehearsal (via kata, kumite, etc) that we use to defend ourselves. We practice a certain block against a certain technique so much because when that technique gets used against us, our bodies know what to do. This is the "rehearsal" you reference. We "rehearse" so that we can act immediately, without having to go through a database of knowledge to figure out how to defend. An actual fight does happen very fast, and its the practice and drilling that helps us use the time we have for defense more effectively. This is also why we focus on bunkai. This move can be translated into a defense against that. Then, we take that and drill it so that it becomes a part of us and then move on to the next technique. So yes, the difference between a martial artist and a non-martial artist is that we know how to move our bodies for defense, but there is so much more to that than you suggest. We know how to move our bodies if someone punches us, or kicks us, or throws any technique at all because we incessantly drill those movements via kata and other practices.