I agree with what many others say. It all depends on when the next gen console gets announced. I wouldn't be surprised if it's before Sony/Microsoft, considering Wii U launched a year earlier and that it has not sold good enough. That said, there is a high possibility the U won't make it to 20 million.

I've just done a calculation: Wii U has sold 7.29 million from Nov '12 to Sep '14 (that's 22 months), so 7.29 divided by 22 = an average 0.33 million units MONTHLY. Let's assume the next gen will be announced 5 years after U's release ---- there are 42 months in 5 years, so 0.33 million * 42 = 13.9 million. From this calculation, if Wii U sells at the same rate as it has from Nov 12 to Sep 14, we should expect just 13.9 million sales after 5 years (Nov '17), which is extremely low compared to the other two.

And don't forget 13.9 may be an overestimate considering that Wii U was announced 4.5 years after Wii's release (instead of 5), plus the fact that Wii U has sold poorly means that the next gen may come sooner than we think. In fact I think it would be better for Nintendo to start working on the next gen ASAP because clearly the U has failed.

EDIT: even with VGChartz's higher estimate of 8.22 million lifetime sales, we'd still only have 15.7 million by 2017 with that same calculation I done above.

Believe it or not, the 9th generation of video gaming is creeping ever closer and is in sight. The 3DS was announced at E3 2010, 6 years after the DS (in a normal cycle). Six years after 2010 is 2016, which, would you believe it, is NEXT YEAR, now that it's 2015.

That said, there is a major possibility that Nintendo will present the next generation handheld in 2016. And although the smartphone game craze has hit them and Sony hard, the fact that 3DS is actually selling very well shows that the market is still large. Can't wait to see what they will be up next.

Or maybe it would be smarter for Sony to step up earlier and announce the next gen handheld, because VITA has failed as opposed to 3DS, so what if Sony actually announce the next gen first?