And they do, they always do(sometimes me included).
Nintendo's in a place almost as good as Gaben & Valve; they know that if you have a product good enough, people will buy it. In some cases, over and over and over. Nintendo facilitates this and makes sure you have many avenues to purchase and re-purchase their products. They have to protect their intellectual properties for legal reasons, but they honestly don't care about emulators and code leaks because it stirs interest and people continue to buy, even when it's otherwise available for free. There's room for improvement but Nintendo's in a great place right now overall.