Ipod and Android gaming are primarily played by people who aren't gamers. Nintendo has no real fear from any handhelp, except POSSIBLY the Vita, but that's still yet to be seen. Real gamers are the people buying games and they will continue to buy consoles keeping Apple and Androind from even becoming contenders.

Allow the 3DS to play videos and there's absolutely nothing an company can do to stop Nintendo. Aside from that, there's nothing Nintendo has to do.