Who would make the games then? You could say goodbye to competent third parties. Nintendo makes profit on both hardware and software. I doubt there would be much motivation to make great software if people were just going to steal it. There would still be good software, but the AAA games would likely disappear. Ofcourse that's the worst case scenario wherein everybody pirates everything. And from what we've seen in PCs that won't happen, but it's still scary to think about it.
"Now, a fun game should always be easy to understand - you should be able to take one look at it and know what you have to do straight away. It should be so well constructed that you can tell at a glance what your goal is and, even if you don’t succeed, you’ll blame yourself rather than the game. Moreover, the people standing around watching the game have also got to be able to enjoy it." - Shiggy
