So why didn't Nintendo just follow the blue ocean strategy again, since it worked so well for the wii? Did they just intentionally design the wii u to be gamecube 2.0, instead of making billions going for the blue ocean?
Because blue oceans are hard as hell to create. It's not something you can do again and again and again. Why? Because theoretically, blue oceans shouldn't exist. From a business strategy standpoint, companies should attempt to diversify themselves enough to fill in gaps or openings within the market. Sometimes, however, this doesn't happen. Gaps go unfilled or even widened, due to narrow-minded red ocean (ie. homogenized) competition. Red ocean competition is something that business has perfected over the last several decades - fighting with cost advantages, greater sophistication along very specific lines and standards. If you have enough money, or have greater technology with which to reduce costs, you have an innate advantage within this form of competition. This is very accounting, finance, and operations / logistics oriented.
Marketing tends to take a backseat in this form of competition. This homogenization leads to the gaps I mentioned before - and these gaps are colloquially referred to as 'blue oceans,' when really they're just market inefficiencies.
When Nintendo came up with the Wii, there was a huge gap in the market. However, following the Wii, this gap has closed up as competitors - both new and old - have shifted into the space. Microsoft with Kinect, Apple, etc.
Blue ocean isn't something you can easily create unless the market is tremendously homogenized and inefficient. You don't do it out of thin air, nor can you dictate that you'll always find a gap within which a blue ocean can be created.
Saying, "Well, why didn't Nintendo just do it again if it wasn't luck?" is a clear sign that the person speaking doesn't really understand what blue oceans are or how they're taken advantage of. Nintendo would love to have another blue ocean. The problem is, they can't find one. Who knows: The next blue ocean may fall into MS's lap, or Sony may be especially suited for it. Just have to wait and see.