Why is so hard for Wii U sell 20,000,000?

[Ryng]

Nitro187 said:

2015 - 2.2 mill
2016 - 1.8 mill
2017 - 1.3 mill
2018 - 800k
2019 - 200k

So... 16 million ish.

Well, that is why i think that 20,000,000 is more probabily than 16,000,000 / 17,000,000 ...

Wii U have sold +500,000 NOW at this point of the year. So, Wii U must sell 500,000 even in the holiday for sell just over 2,000,000 this year... under 3,000,000 is seriusly low.