I think a lot of people are tying way too much into the stock price and trying to apply it to the company as a whole.
I'm not saying Nintendo doesn't need a course correction, because they do. Hell, they need a whole new compass let alone a new course.
However, the stock price is a very emotionally-charged aspect of a company. Look at Apple when they dipped down into the 300s in share price not long ago. Everyone was calling doom and gloom, the end of the Apple reign, etc. Not me. And I fucking HATE Apple products. But I saw a company sitting on mounds of cash reserves and not going anywhere anytime soon.
I see the same thing with Nintendo, to a lesser extent. They don't have the cash reserves that Apple does, but they have IP reserves, and in the videogame biz tried and tested IPs are as good as cash.
Nintendo isn't going anywhere. They need to change, and desperately, but they aren't going anywhere.
I wouldn't mind at all if they go the route of Sega and become a 3rd party publisher, but at the same time I would be ecstatic if they release a REAL console that isn't a generation or more behind in tech, that supports the latest media both gaming and not, and that has an online infrastructure that isn't completely laughable, although the 3rd point isn't a must because TBH the games that Nintendo really does great are much more suited for couch co-op and group gatherings (Mario, Mario Kart) than they are for online play, or else they're mostly single-player affairs like Zelda.
But people prophesying doom just because the stock price dropped massively are forgetting one thing: shareholders are emotional, fickle beings. They despise bad news, and the 18% dip followed by a recovery and only a net loss of 6% speaks volumes to that.
If they keep going on the path they've been on, then yeah they'll buy themselves a quick ticket out of the video game biz. But if they make the changes that need to be made, they can bounce back from this.