How do you plan to measure this, exactly? I get your point that the end goal is competent adults, not test performance per se, but I've firsthand seen how my own kids can fail to get a concept well enough, and that leads to not getting the next concept, and so on. If you're not good at addition, you won't be good at multiplication, and so on through high school and you're just HOSED when you need to be good at trigonometry.
Come on, people. Science works. Things that work are...testable. If you're advocating some educational strategy, but reject the notion that it's testable, you're rejecting basic science. If that describes you, kindly keep your hands off education policy.