Few points:

(1) I don't think Apple would buy Nintendo but...

(2) If Wii U flops worldwide (as many expect) then Nintendo's default option is to go the Sega route and just produce software.

(3) Unlike Sega however, Nintendo's IP is worth substantial market share so I'd expect a major bidding war for exclusivity. Exclusivity would also allow Nintendo to continue to develop for a single mobile and home platform as they do now.

I'm not sure that apple itself has nothing to offer. I have a feeling it is only a matter of time before apple releases something that is of serious interest to gamers.

It may not be a games console as such but think something with a large screen , an app store and some new input method that lends itself well to gaming.

Apple's announcement of what will likely be the iPad 3 coincides with GDC. I would think an iPad 3 + 1080p AppleTV is a compelling console replacement. I bet that is their move: to make your TV a monitor for the iPad. That solves the interface issue with TV in one fell swoop.

I think this could work well for some categories of games, for example strategy games but there are still many popular games this wouldn't work so well for at all(driving games, fps etc)

So either they will focus on a different category of gamer/games or there will have to be some other more game specific input device such as a controller.