It is not remembered because it is not used. Math is a literacy and about 20+ years behing reading - Reading across the "content areas" - around a long time. "Math across the content areas" - a long way off. In math applied is weak; abstract is king. I recall the quote "Why do I need to learn this math stuff? Oh, you need it for your next math class!" Relevent only for the next math class.
The only chance we have is to hammer away at the stuff bit by bit every day for years. Even then it does not work...Give me a kid who wants to learn the stuff—well, twenty hours or so makes sense."
Pretty far out; I like it. Thinking about the depth to which grades are in the system - credits, transcripts, GPA - both as a sign of progress and or understanding. Also thinking about assessment and grading - assessment of learning versus assessment for learning...... Great post!