Do you think until someone makes a mistake? Nor really, as these things should take only split seconds, there is a limit to the human reaction ability to digest and redirect an offensive or defensive move.
Lets talk about efficient attacks and efficient counter attacks to make the long story short:
Training in efficient methods of attack emphasizes the fastest way the human body can reach a pressure point form any possible distance, generating sufficient force to impact this pressure point to the point it buys you time to keep controlling your opponent from a split second to infinity.
Training in the most efficient methods of defense emphasizes the defensive evasion, deflection or redirection of a force of impact or push and pull following up with the most efficient countering force which is the force of impact.