I totally agree with your point. This is similar to what Stephen Covey discussed in his book ‘The 7 Habits of Highly Effective People’, particularly in Habit 3, ‘Put First Things First’.

In his time management tools, he mentioned that we should spend most of our time in Quadrant 2 (important but not urgent), instead of spending our time in Quadrant 1 (important and urgent).

Using your terminology, it makes sense that willpower relates to managing Quadrant 1, whereas brainpower relates to Quadrant 2.

Thanks for sharing your insights.