My prediction:

Wii U: 40 million
PSV: 20 million

Wii U: 60M
Vita: 25M

:3

Well yeah I guess after Wii's success was understandable to think that, but people nowadays thinking WiiU can reach 35 millions is...

I honestly still think Vita will get Monster Hunter at some point and don't think 18m is out the question in Japan. 3DS is slowing down rapidly and if the Vita repeats the PSPs second wind and beats out the 3DS for their twilight years I think 40m+ is achieveable especially with those infamous PS legs.

Wii U is the other end of the extreme imo, it seems that everyday its gets more bad news and people (including Nintendo themselves) are consistantly revising their predictions.

Even after todays Resident Evil remake HD announment makes me feel 23m is getting further and further away. It might only be a remake but it speaks volumes of 3rd parties perception of it.

Vita 20 million.

With no signs of Sony putting any effort in developing the Vita's market in NA and Europe, it's going to remain a novelty loved by PS and handheld fans only.

Wii U 35 million.

Though 3rd party is weaker than ever, Ninty's core franchises(Mario kart, smash) are better known. Has some good indie games and a major slice of the NFC gaming segment.

Wii U and PS Vita are pretty much commercial failure. People need to accept this. Same fate as dreamcast.

Vita with MH Wont change vita's fate. It'll help out alot, but 18mil? 3DS will barely hit over 18mil lifetime and that has 3 MH titles and Pokemon, DQ Remakes/Spinoffs/ Animal Crossing/ Youkai Watch/ etc. Vita also is only at a little over 3mil (wont even reach 4mil by years end) in japan. 

PSP also at the same time is doing much better, and MH peaked. Its not going to repeat itself. Also the West... US will probably have Vita at 2.2mil-2.5mil by years end. Vita will have the best legs in terms of HW, but i think its already too late.

Nowhere near the same fate as the DC. If they were they be already dead

1. I am speaking from a business point of view.

2. In our university one of our lecturer said, "Know your limits. Know when to pull the plug. Its better to cut the tumor before it spreads". Both Wii U and PS Vita are failure.

3. I know it will be very hard for both nintendo and sony to pull the plug of these two. It will impact future systems (I doubt if there will be any new sony handheld). Better option is to slowly kill these two. Suddenly killing these two will impact. So slow killing is best option.

1. No problem

2. Which is a good saying, but for Vita/WiiU Sony+Nintendo cant. It will F*** up Consumer trust (6mil+ Users for WiiU and the 8.5mil+ for Vita) if they just let them go now and proceed with the next installments. This decision affects future Decisions/etc.

3. They cant slow kill the systems. Vita is doing decently in japan, and you dont kno if they arent making profits from it. As for WiiU, killing it off in the next year or 2 is too early. Thats exactly wat happened to Sega.

Im not saying WiiU isnt effecting Nin, cuz then i be lying. But letting go the wiiu where nost of Nintendo Hardcore fanbase is early isnt a good sign at all. Best they can do is ride it out and make the best profits they can. And WiiU isnt out just yet. Give it time, plenty of systems didn't go into full gear this early. 3DS is the only system out now with practically 100% of wat we kno the HH will do lifetime.

WiiU Successor should come no earlier than 2016 Holiday. My guess is 2017 and the HDS late 2015/2016!