Now that we have PS4 details, I'm worried about Nintendo

I don't know if you're playing close enough attention.. they didn't so much "hang on to life" with the Wii as they did make a ton of money which could easily support them throughout the Wii U's lifespan if it continues to undersell. There isn't really a way to use what is currently happening with the Wii U in predicting the end of Nintendo, for a lot of people I think that is just wishful thinking.

I really don't think anyone at Nintendo would consider the "hardcore success" thing a failure when it also represents the time they were crazy profitable.

There are a ton of reasons to be worried about Nintendo, but none of that really has to do with PS4 having a similar feature to the WiiU. They aren't really going after the same market.

Really? It completely destroyed their software attach rate. So much so that they refocused their efforts on trying to appeal to the hardcore crowd in the WiiU (and, in turn, has lead to the master of none result).

It's so early in the generation that anything could happen. Just look at the PS3. I was one of the many that wrote Sony off and felt like their end in the console race was approaching. By the end they've quickly become my favorite and have me incredibly excited for the next iteration. Nintendo has the advantage of not really directly competing with either MS or Sony and possibly the most loyal fanbase of all. As long as they keep making amazing first party games they'll be fine.

I don't know if Nintendo will be around forever or not, but even if not, it would be interesting to see how much longer it sticks around. I hope theirs no worrys about Nintendo.