Nintendo was never in financial danger of falling out of the industry, certainly. Their relevance was on the downslide, and they probably would have left the industry if Wii and/or DS had failed (Iwata said it himself, though not in those exact words)
But now Nintendo probably has one helluva war chest, and they could stand a generation or two of GC-style failure, so long as they sustained profits throughout, as they always have
Monster Hunter: pissing me off since 2010.