I dunno, we'll have to wait and see.
Though I did think about it, and if Nintendo died I don't think I'd play video games (for the most part ) anymore, not new ones at least. I noticed that the majority of the games I buy are for Nintendo systems, and while I do buy 360 and PC games, but not nearly as much. I mean, I buy The Sims and Elder Scrolls games, as well as Dead or Alive, Soul Calibur, and (maybe) Final Fantasy, but if Nintendo were gone there'd be no Gyakuten Saiban (Phoenix Wright), no Zelda, no Kirby...and with the competition gone I'm almost sure Sony's games will grow stale too, and continue to be saturated with FPS' and...well...it would suck. Though there always has to be a triumvirate, and if Nintendo died a new company would come to take its place, possibly a better one.
But then again, their death is unlikely at this point in time, possible, but unlikely.