Here are the combined yearly sales of the PS3/360 and the XBO/PS4. Using VGC Data, figures rounded to thousands.
Switch tops the Gen 7 combined peak if it passes 28.4M sold this year (needs to sell 8.6M in the final 7 weeks of the year - it did 8.1M last year so this should be easy).
Switch tops the Gen 8 combined peak if its passes 27.4M sold this year (needs to sell 7.6M in the final 7 weeks of the year - it will be close to this by Cyber Monday IMO).
How about straight up best years of Gen 7 and Gen 8 consoles, without lining up the years? Gen 7 stays the same (2011 for both). Gen 8 goes up to 28.2M (PS4 2017 + XBO 2015). So the story doesn't change.
Point is, 2020 NSW is on pace to pass the combined best year of sales of both 360/PS3 and XBO/PS4. That's with supply/production issues hitting the entire industry (RTX 30 series, Ryzen 5000 series, upcoming RDNA series, NSW, PS5/XBS - everything is struggling to meet demand right now). IMO if Nintendo could have produced/shipped 35-37M NSW consoles this year, they would have. Yet they are likely only going to sell/ship 28-32M this year and this FY.
Those problems are not going to go away come January. Nothing magical is going to happen with PS5/XBS that's going to boost them past the performance of the previous 2 gens (save for Series S price point of $300 - we will have to see how that penetrates the market, especially outside of the US). Reasonable expectation though, is that the combined sales of both Gen 9 consoles should hit 27-29M some time in the Y3-Y5 range (counting 2020 as Y0). NSW I am certain will stay above 30M in 2021, and at the very least should hold the fort above/around 25M in 2022 (we will have to wait and see how Nintendo's hardware strategy plays out regarding Pro vs. Switch 2).
So I think this thread/prediction is too conservative. The Switch should hold up well vs both XB/PS combined in the next 2-3 years. PS5 alone is too easy of a target (especially at $500 price point, especially with Sony not supplying a heavy share of the $400 SKU).