I had a large amount of willpower in younger years ... particularly in my teens and 20's. I managed to accomplish just about everything I set my mind to ... a tough military academy, paratrooper training, marrying the "girl of my dreams", a successful career, fighting in a war, and some others. Then it all seemed to unravel. The marriage was a sham, the career was a facade, I never used my paratrooper training, and the war was a big eye opener. Well, at least the academy was worthwhile. I began to consider how little influence I really had on life and how maleable reality is. I discovered that sometimes the optimal solution is to exert less willpower for a more stable or equitable existence. Nowadays my will power is more situational. If I feel it is worthwhile, I will pursue it ... but gone are the days of blind idealism. I've also found that the people in your life can be more important than some arbitrary goal.
Edit: I've read that NTs tend to develop a min/max perspective to life. Minimum effort for maximum results. Perhaps that translates into my present paradigm. I've also tended to value knowledge acquisition more the older I become, rather than concrete accomplishment.