Oh. Well, according to Nintendo's own internal sell-through figures, the Switch sold something like 25-26M in 2020, bringing the lifetime total to about 74M, up from 48M LTD at the end of 2019 (Nintendo's sell-through figures are rounded down to the nearest million, so there's a slight margin of error). So, if I had to guess actual yearly sales, I'm thinking of maybe 21-22M this year and 16-17M in 2022. Beyond that the margins of error get bigger (as with any long-range forecast) but assuming the Switch's successor releases in March 2024 (giving the Switch a 7-year lifespan), perhaps 11-13M in 2023, 4-6M in 2024, and 2-3M in 2025. So, that's about 54-61M in total from 2021 onward, giving us a lifetime total somewhere in the 128-135M range.
Considering how the Switch has been tracking against the DS (rapidly falling behind in the U.S., and massive and likely insurmountable deficits in Japan & Europe), I don't see it matching the DS, and I think it'll fall considerably short of the 150M mark. That's the main reason why I think the Switch will sell somewhere closer to the 130M mark.
First off, thank you for actually putting out your yearly predictions. Your percent drops seem somewhat reasonable, and I would advise you do not use Nintendo's internal sell-through estimates. As strange as it seems, their estimates have become increasingly unreliable.
Second off, I will admit that DS will be near unbeatable in Europe for Switch, and though it seems the DS's lead against Switch in Japan is insurmountable, there is enough life in the Switch for it to beat the DS. US is a bit of a toss up for me, and could go either way. But, RotW will be instrumental in the Switch's effort to beat DS.
Thirdly, My personal predictions based on Switch sell-in data:
2025: 4M (this is when Switch successor launches, Q1 to be exact)