The last section contradicts itself. If lack of desire will make you lose always, what is the point of a "perfect technique"?
For the best of my understanding, the Japanese believed in "empty mind", "wishing while not" and "being ready to die" instead of strong desire to win, as a way of achieving victory. I think this belief \ concept is fundamental in many JMA.
Perfect technique is a goal unto itself, it has no attachment to winning. From the later samurai works like Hagakure, I'm sure that you are correct, the samurai would say that perfection of self is victory. However This may mean you will lose the fight.
As I said it's a philosophical debate; you can have perfect clean technique, but if you face someone who approximates your ability, who will sacrifice perfect, clean technique to achive victory, you will most likely lose the conflict. This would mean if you're fighting for something you value beyond your own existence that will be lost as well (your family, a gold metal, respect, etc.).
Now in training, this philosophy is a great one. It doesn't really matter if you win or lose your little dojo randori, nothing is on the line. You should be willing to sacrifice a small victory in order to achieve prefect technique.
The problem with Kata is that you never face the pressure you will face against resistance. Thus you will never acclimate yourself to using your technique under pressure. If you can do ikkyo a million times perfectly in kata, that has very little bearing on how you will do it once under pressure, in an ever changing situation.