Why is Jumpin's post correct?
The issue are indeed retail sales, i.e. demand in the marketplace. Retailers won't buy the necessary units if the consumer demand isn't there. Nintendo defines 'shipped' as 'sold to retailers', so while it is clear that here is no problem to manufacture 20m units during this fiscal year, it's also obvious that those 20m won't be shipped if retailers aren't ordering them.
The commonly brought up idea of channel stuffing only works for holiday quarters, because outside of that retailers can't be convinced that there will be more demand than expected. The consequence of a stuffed channel is that Q4 of the fiscal year will be soft, because retailers have to work through their excess stock before they buy more units from the console manufacturer. If Nintendo for example shipped 11.5m in Q3 of this fiscal year while units are piling up at retailers, then Q4 would have a hard time to be above 2.5m.
zorg1000's example supports this despite him thinking otherwise. Sell-through of the PS4 from January to March 2017 was comfortably above 3m, but shipments were under 3m.
I'm going to knock this one out at the premise on which your whole argument sits.
For your post to be of any contradiction against mine, you'd have to demonstrate that the demand isn't there.
The Switch is selling quite well, and with an already healthy 2019 lineup announced with headlines like Pokemon coming up in 2019, there is no reason to think that consumer demand won't continue to be there, and high; and it's evident for any retail chains that this is the case.
I describe myself as a little dose of toxic masculinity.