Retail presence in gaming is important and the decline of the Nintendo shelf space is alarming. During the Wii/DS era, you would have entire isles devoted to each, they would have their own end caps, be featured in front of the store for big releases, etc. Now, even with the 3DS being available 3+ years and the Wii U for almost two, on average, in the stores I frequent, shelf space is all combined (Wii, Wii U, DS and 3DS) or the total space is just one isle.
The Nintendo family of products no longer offer the same value proposition to retailers from say 2006-2011. With the Wii and DS retailers were able to push accessories which have very high retail markups, thus high margins for them.
Xbox for the most part has remained the same since 2005, commanding a lot of space with the X360 still and growing for Xbox one, the same with the PS3 and PS4. Most of the Vita space I have seen is coupled at the ends of PS3 isles and is a drastic reduction from the height of the PSP days, but the Vita is not selling well and (the console itself) is never stocked well.







