The influence both Microsoft and Sony endure are from the gaming public. The public wants something and Sony and Microsoft just want to give their 'clients' or 'potential clients' the ability to have a more complete experience on their console. It is all about the market. The PS3 and X360 can do both Casual and Hardcore games, hence they are trying to offer both. If Nintendo wishes to offer an HD experience to their users, they are free to do so.
You cannot legitimately put forward a notion that companies such as Microsoft or Sony are copying Nintendo since you can't 'copy' another company by catering games for a 'genre'. Both Microsoft and Sony had games that catered for the casual gamers long before the Wii-Casual Reference came about with games such as crash bandicoot, Banjo Kazooie, Viva pinata, Buzz and many games that came out on the Xbox and PS2.
Would you say nintendo was trying to copy the PS3 and X360 by allowing games on it such as the conduit? Or better yet, Metroid prime?
I am a Gamer... I play games and not consoles. I have a PC and Console on which I game... I like games. End of Story!
