Why do people believe that a console like PS4, tracking ahead of all competition and even its predecessors, with 60% sales share will end selling worse than all other PS consoles? I don't get the logic in "outselling its predecessors means selling less than them LT".

Despite that, it still includes Wii U beasting to 50M and X1 regaining lost ground.

Because of my FIRST sentence.. This will not be a 8+ year generation.  I believe it will only be 5 years..  so that takes away 3-4 years of sales...  I still have the PS4 outselling the PS3 in 5 years span..    The X1 was ahead of the X360 in its first 6 months.. being way more expensive and in way less countries..  so I still see it doing decent in the long term.. with the price drop especially.  

But it all comes down to a shorter lifespan for this generation.

I really don't know why you think this generation will be shorter then last generation

If the PS3 came as close to surpassing the Wii as it did and it sold poorly for the first couple years, the PS4 easily has a chance to pass the Wii within seven years.

4k is the biggest reason.. along with several others related to GPU/CPU.  4K sets will be the norm in 3-4 years..  PS4 and Xbox One while capable of 4k video.. will likely NOT do 4k (As they can't even manage 1080p all the time).   

The call for 4k consoles will come quick. The PS3/X360 came right at the beginning of HD 720/1080p and took advantage quickly. If both of those consoles would have shipped without being able to hit 720p, they would have died quickly.  I think since neither console is capable of 4k Video Games..  we will see PS5/Next Xbox earlier..  I DO think that these will be more transition consoles also. Similar machines with backwards compatbility just with upgraded CPU/GPU/Memory (since PC arch now).    4K standard.

Thanks Shadow, your analises are always nice to read.

Well, gen lenght is debatable. But is is still tracking ahead of PS1 and 2, both with 5 year normal cicles. So your point still isn't valid.

It will stay ahead till christmas 2016.

Makese sense for now -- Wii was a huge seller in Japan early on, PS4 has failed to reignite the console industry, so that alone should keep Wii ahead for the early part of its lifespan. On top of being completely sold out in North America + Europe, the Wii was bringing in 50-80k a week in Japan through 2007. 

Once again. If the next consoles reach 4K that will make this gen longer, not shorter. PS2 to PS3 was a jump from 480p to 720p. It's roughly 2.5X more pixels. 1080p vs 720p is 2X more pixels. 4K is 4X 1080p. You need a pretty beefy GPU to do that. Current high-end PC GPUs will suffer to do it keeping visuals at current console levels. If you get a GPU 4X as powerful as the PS4 one (we could even use a 3X more powerful since resolution impacts only the stages during/after rasterization but these are by far the more demanding ones) you will have the same level of graphics than PS4 but at 4K.

By Moore's law, this GPU will be possible with the same power consumption than PS4 in 3 or 4 years. But that is with the same visuals. You can't just up the resolution and launch a console and expect people to buy by double the price during the peak of previous gens. You need to improve visuals. So, for 4K, you need 4 years just to reach the resolution, only after that you can start improving visuals. Maybe even next gen won't be 4K ready after all since 1080p content looks good at 4K because there isn't any need to upscale it to avoid quality loss (or you can render at 1080p and just upscale with a decent AA solution without much costs). Even PC games will get less 4K attention because current high-end, multi GPU PCs are only rendering at 4K because all games use 7th gen tech that simply doesn't push any boundary. After the real 8th gen games kick in, GPUs will start having trouble and 1080p will become the sweet spot. Despite that, you gotta balance you game visuals. A 4K game with 7th gen level visuals will simply look garbage compared to a 1080p 8th gen level game (that doesn't exist even today).