Quadrants are fine when they point to more productive re-framings of the "public X" problem. As implied by you & maybe the article you mentioned, the boundaries

Quadrants are fine when they point to more productive re-framings of the "public X" problem. As implied by you & maybe the article you mentioned, the boundaries of the quadrants are where the theory is likely to fail.. So, if we focus on these boundaries, as honest and curious scientists & engineers, we might chance on new avenues