My father don't give a shit about video games or video games market. But he was slightly interested since I have bought for 3300€ of Nintendo shares when the Francfort value was around 231-232€.
I told him that since launch and less than 2 years later, they had not made any official price cut on the Switch. He said that this was a proof that they are sure to reach their goal. OR at least in a range of -5% which means 19M and would be considered as a success.

I know it’s purely anecdotal, but I’m in Canada and it seems that at the store level, Wal-Mart and EB Games are out of stock of both Smash and Switch. Knowing how EB Games work from the inside, I pretty much expect the shipments to be bigger in January than normally, I mean that normally we had enough supplies after the holidays for a few weeks without needing any replenishments.

With the latest NPD figures, vgc estimates the Switch has sold at total of ~14M units. With no big releases on the horizon it's safe to rule out that the Switch will ship another ~6M units this quarter ...

VGC had to increase the numbers several times. While we know several countries now, it's still possible that Switch is undertracked

However, even if the console is undertracked, reaching those 20M is almost impossible by now, though 18-19M are still in the real of possible.

VGC under tracks the switch so it may be 14.5-15 M units sold.

Shipped is usually 1M or 1.5M on shelves so it brings the total shipped as os of end of 2018 to 15.5M at least and 16.5M at best.

With that said i think 19.0M is a safe bet but i can still see the 20M happening

That prospect seems unlikely by a wide margin considering vgc also adjusted the figures up for the other territories as well in conjunction with the NPD numbers ... 

That's incorrect. You're suggesting it needs another 6m sell through, but it doesn't. Nintendo's forecast had it doing 20m shipped for the fiscal year (April 2018 to March 2019). Honest question: do you know the difference between shipped and sold? VGC numbers are sold, not shipped.

PS: If the 10m shipped number for this quarter is correct, Switch will be at 15.1m shipped as of December 31st, needing another 5m to reach the goal. I agree with you that even with that it's impossible if those are the numbers we'll be getting next week from Nintendo, but as food for thought, Switch did ~3m last year on the same quarter. This year, with the info we have, it's tracking well ahead of last year's January (about 40% higher based on MC), so we can realistically expect it to ship anything from 3.5m to 4.2m, which should put it between 18.6m~19.3m for the fiscal year. While not reaching 20m, it will be quite close (will miss the mark by less than 10%) for sure).

Looks like it will be 3 million short

IGN has it at over 32 million LTS as of right now. I think its going to be a lot closer than people thought initially. Commendable.

They will beat both new prediction with 18,5 M consoles and 115M software. This will be a happy end on April 31st.