Mastery Learning and Grades

My son broke this board during his latest Taekwondo practice. He is gearing up to earn his next belt in a couple days. It took him eleven kicks before he could break it. His first ten attempts did not produce the desired result. After his final, successful attempt, his teacher told him that he was very proud of him. There was no discussion about the first ten attempts. But what if he had been told that, even though he broke the board, he was not ready to earn his next belt because it took him too many tries to break it in the first place? I am afraid that this thinking is still way too prevalent in schools today. Just because you didn't turn it in on time, or because you didn't reach the same level of achievement as your peers, or because you took longer to learn than someone else, does not equate to a grade that reflects less than mastery, if mastery was indeed achieved. This thinking is wrong, even downright unethical. And if someone in the educational world is still handing out zeros, please stop. Like tomorrow. Let's not confuse the journey with the destination.