Nintendo will have Mario, Pokemon, their own games. They'll have the ability to invest consciously in new IPs, and even perhaps buy some exclusivity if necessary. So no, "kill" is too strong a word.
It may become a sort of leadership in sales, which it kind of is already. It may start eating into all of the other sales, but as far as Dreamcasting Nintendo handhelds and others, I have a hard time with that idea at this point.
It just screams of raging wishful thinking turned into logic.