4) The large majority of primary teachers simply do not know how to teach math. They treat primary kids with kid gloves and continuously low-ball kids with laughably easy math. Drills, rote, basic strategies are shunned in favour of impotent and ineffective strategies. "Show your thinking" should be axed. Instead, practice these 100 questions until you have them down-pat, then move on. I've gone to workshops where I've seen primary teachers in groups make basic errors. Laughable.
5) Faculty of Ed deans and math departments are a major component of the problem. They act like impudent gods telling teachers how to teach math. So few deans have actual math backgrounds. Anne Stokke does. 
6) Gov't is another problem. The curriculum is beyond bloated.
7) Teacher colleges pump out cheerleaders in their 20s at the primary level who are frankly uneducated. Ask your kid's teacher her background and pick: psych or sociology. 
8) Lack of rigour in education. It's all social promotion.