This is the consequence of not teaching domains of problem-solving through actual problem-solving. You see the same thing in math. I had an excellent practitioner of this method for AP calculus. I learned limits by attempting to find the area under a curve using ever-shrinking rectangles, until we got to pushing them to zero width. And now, 15 years later, I still remember the concept. I don't necessarily remember how to do any particular problem involving limits, but I know what limits are and when they apply to a problem.