I honestly don't think Nintendo cares that much. They want to make it secure enough that pretty much everybody will buy the games for real, but they won't spend an insane amount of effort making an unhackable system just to go after the small percentage that do. Just going on this site alone, I estimate maybe no more than 1,000 people are actively hacking the Wii U, out of the 13 million systems sold and 90 million games sold. Even if 100,000 people were hacking the Wii U, that would account for only 0.75% of all users and a small fraction of game sales lost.