I don't think the willpower/training distinction is as clear as his post suggests.
If I had more a much stronger desire/willpower than George St. Pierre to excel at fighting, I would train harder than he did... and I would be a better fighter. The man is great because he's trained hard, worked out, etc.
Willpower may not be enough to make you a success on 30 seconds notice. But you can get better at almost anything over time by working at it.
Part of the problem with the St. Pierre comparison is that he's in the top 1% of fighters worldwide. It's unlikely that even with far greater motivation you could see dramatic gains over him as a fighter. There are also genetic factors when it comes to physique that are out of either of your controls.
Though I do agree that you can get better at things over time - in fact I advocate developing habits as a way of "improving" your ability to manage your behavior and augment your willpower.
The reason GSP is in the top 1% (more realistically the top 5 on earth) is that he works so hard at it. Despite his natural gifts, he wouldn't be able to compete at a high level without training... which he did because of his willpower.
"I would train harder than he did... and I would be a better fighter."
Training like crazy - great. Physically gifted (fast-twitch muscles, size, reach etc.) - great. Those two factors build a great foundation.
But nothing replaces fight time. Until you've put yourself in competitive combat situations, there is no way for you to truly understand how to react naturally to a fight situation. Honing your fight craft and anticipation is the difference between victor and vanquished at the very top.
If I had more a much stronger desire/willpower than George St. Pierre to excel at fighting, I would train harder than he did... and I would be a better fighter. The man is great because he's trained hard, worked out, etc.
Willpower may not be enough to make you a success on 30 seconds notice. But you can get better at almost anything over time by working at it.