The important part is mindshare of what the record is. Independent on what is discussed on this forum, we need to look at what the general belief of PS2 sales actually is.
Outlets with greater audience reach than VGCharz seem to take the 155 million number as the number to beat. If Switch does go 155million + the majority of publications will declare the Switch the winner. And with that the mindshare of gamers and non-gamers will be that the Switch is the best selling console.

Some references to make my point:
https://www.forbes.com/sites/olliebarder/2024/02/07/switch-reaches-13936-million-sales-globally-yet-to-surpass-the-ps2/
https://www.nintendolife.com/features/poll-do-you-think-switch-can-catch-ps2s-total-sales-before-switch-2-arrives
https://www.gamesradar.com/the-nintendo-switch-is-about-to-become-the-second-console-to-sell-a-billion-games/
https://www.pushsquare.com/news/2023/02/ps2s-best-selling-console-crown-in-jeopardy-as-nintendo-switch-passes-ps4
https://www.techspot.com/news/101775-nintendo-switch-closes-playstation-2-all-time-best.html
https://en.wikipedia.org/wiki/List_of_best-selling_game_consoles

From Nintendo's perspective sold to a retailer is very much sold. It does not matter if units have not been sold through to an end consumer.

The shipment numbers always accompany financial reports, so we need to interpret the word 'Shipments' in a financial sense, not logistics (like in-transit). Essentially it's to back up their financial numbers. In this sense 'Shipments' is to support revenue and cost of goods sold numbers, in that sense shipments are sales for Nintendo.

If VGChartz is at all reliable, then Switch is selling ~2.5mil Q4F23, likely putting shipments around 141mil. **Worst case**, Switch pulls 2mil both in Q1 & Q2F25, 4mil Q3F25, and 1mil Q4F25. At this point, Switch hits 150mil shipped. (More realistically, we should expect around 152-153mil.) In the pessimistic scenario, that’s still only 9mil for Switch to dethrone PS2. In the expected case, only 6-7mil. It’s hard to make an argument against the Switch passing DS. The PS2, however, nothing is guaranteed. I’ll remain optimistic, especially if the successor does play-along with the Nintendo Switch branding (Like how GBA was to GB, 3DS was to DS, SNES was to NES, etc. This situation may lead consumers to view Switch OG/OLED as the cheap alternative to the new console).

Yes because the PS2's last official figure is 155.1 million reported by Sony. To protect the PS2's legacy, the goalpost was moved. People on gaming sites thought moving the goalpost to 160 million would keep it safe from Switch. Boy were they wrong lol.

PS2 160M number didn't just came after the Switch started to get close. 160M for the PS2 was mentioned long before Switch even entered in it's peak period, and was pointed 160M because it's way easier to round up the number to 160, than every time to put 157 or 158 or 159M (and possibly explain why and how). There were even thread in reset era that calculated the numbers range to be between 159 and 161M (so even barely above 160M). And that back in 2018, when Switch just started it's life. (So there is no connection to Switch here whatsoever).

Also I am on the opinion that if something is so strong and powerful, some small % of difference, won't stop it to beat anyone or anything. Therefore if the Switch muscles are so big, then 160M won't be a problem. So even if the real PS2 numbers are let's say 158M, 160M shouldn't be a problem for the Switch. If 160M becomes a problem for the Switch, than it's really debatable it's muscles or those on the PS2 are bigger.

Another thing is 160M is used as a point of which there won't be any doubters about if Switch passed the PS2 or not. Cuz at 157/158M there will be. And with a reason. As many people over the web calculated already (as this site even too) PS2 has finished anywhere between the range of 157 and 160M. Of course PS2 sold units after that 155.1M announce from sony, almost a full year prior to them discontinuing it. The low it is calculated as a possibility is at least 2M, therefore a minimum of 157M is a lock. Either way, again, if something is truly the best of all time (this goes for everything in life, not only some console here) it should prove that by beating it's closest rival by a good amount of difference, so a true domination is demonstrated. Well for console some 2-3M isn't a true domination, but it will at least help doubters, to not be able to argue about whether or not Switch has passed PS2. That's why the target is 160M. Moving of goalpost about the PS2 is really not needed. The system has done what no other system has did. Sales of over 155M. Most likely in the range of 157M - 159M. Sales of 160M for the Switch will truly shut the mouth of every defenders of the PS2. Well maybe there is the debate of home console vs handheld/hybrid then, but still the best selling is the best selling. If Switch reaches 160M, it will be the best selling, and no one can doubt it. If Switch finishes at the range between 156-159M a lot of people will argue and debate about this.

I see your point on the 160 debate. But in the end here at VGChartz we are a tiny corner of the internet. The decision on when Switch passes PS2 is made by larger outlets like Forbes, Bloomberg, IGN and the likes. It's those reporting that will form the gamers and non-gamers opinion on what sales numbers Switch needs to reach to take the crown. And I'm willing to bet that if Switch goes beyond 155M, that's exactly when these publications will do so.

I agree. They will. Does not make it true however. Just as they are writing the sales as 155M not exactly true. But Sony are here to blame too. Maybe they will come out with some official data regarding the PS2 final numbers.. who knows. Either way, the chances are pretty big that If Switch passes 155M will reach 160M too. Cuz where the 155/156M are, there are the 160M as well. It is slim chance for the Switch to finish in the 156-159M range, let's say it like this. So all of this may be pointless.

Maybe Shawn Layden will post something similar to this, but with the PS2. He revealed the EXACT figure the PSP sold.

This page (https://sonyinteractive.com/en/our-company/business-data-sales/ ) has the PSP at "More than 76.4 million (As of March 31, 2012)," while the post from Shawn Layden revealed the PSP sold 82,523,607 units with the final unit produced on September 26, 2014.

Shipped ≠ sold, and I think we all know that. Obviously even if the Switch didn't have any more units shipped to Japan, unit sales will still eventually exceed those of the DS since there's enough supply left for it to do so. Doesn't change the fact that the Switch hasn't passed the DS in sales. Let's not split hairs on this, okay?

In any case, do you really expect the Paper Mario 2 and Luigi's Mansion 2 remakes to move a ton of hardware when their original versions and other entries in their respective series didn't? I know there's a lot of people here that have a very loose definition of "system-seller." I mean, I suppose even some obscure niche title that only sold 100k copies could've been the one to get a few random people to buy a system. But not every semi-noteworthy title actually causes noticeable upticks in hardware sales (there's been at least a couple of occasions where I was told some game would be a major system-seller only for it to come and go with no bumps to hardware sales). The fact of the matter is that it's only a handful of big games that have any major impact on hardware, and the effect of any single title is always relatively short-lived (usu. a month or two at most, many only a single week). Also, Nintendo releasing several smaller titles in a system's last year isn't anything new. Obviously they're not going to leave these last 12 months before the Switch 2 releases (assuming a March 2025 release date) fully bereft of first-party software for the Switch, but what the Switch is getting won't prevent or even slow down continued declines in sales.

By far the biggest thing the Switch still has left, the only thing that can move the needle on hardware, is the upcoming Pokemon Legends game, but that's not due out until next year. I wouldn't be surprised if it's a cross-gen title, and even if it's not, the Switch 2 will almost certainly be backwards compatible (which could diminish the game's impact on Switch 1 hardware), and most people that bought a Switch to play Pokemon have one already (these late-life Pokemon games always have greatly diminished impacts compared to earlier titles on a given system). We might see a solid but not massive bump lasting a couple of weeks, but that's it, and that bump will be to sales noticeably lower than current sales. That one game by itself won't be the thing that pushes the Switch ahead of the DS.

As for the U.S. vs. the rest of the "Americas" region, keep in mind that the U.S. has consistently been at least 85-90% of Nintendo hardware sales in the region since Nintendo has been releasing systems. Canada represents most of the rest, and Switch sales in Canada have consistently been about one-tenth of U.S. sales. The Switch will probably at best sell 3.5M this year in the U.S., putting it at a bit over 48M lifetime, still over 5M short of the DS's lifetime total. If it only sells 3.5M this year, then I would argue it has zero chance of selling another 5M+ after it's replaced. Unless Latin America & the Caribbean can somehow match or exceed U.S.+Canada sales from here on out, then it's going to be hard for regional sales to match or exceed those of the DS. Even if it does beat the DS for the whole region, it won't be by much, and not enough to make up for the massive deficit in Europe, even if you combine the Americas with the Switch's lead in Japan. As I said, the Switch's ability to beat the DS worldwide is going to depend entirely on markets outside the Americas, Europe, and Japan making up for the net deficit from the main three markets.

This is the last full calendar year the Switch has before being replaced. A large majority of the rest of its lifetime sales will come in the next 12 months assuming a March 2025 release date for the Switch 2, so whatever milestones it can still pass will depend on how well it does this year. Given Nintendo's track record over the past 25 years, I am not convinced they will give the Switch the support it needs for it to not fall off of a cliff once the Switch 2 is released. If the Switch does manage to beat the DS worldwide, it probably won't be by much, and not until well after the Switch 2 releases.

No, I don't expect Paper Mario and Luigi's Mansion to move a ton of hardware, because that's not how it works to begin with. The two of us have had discussions about Switch's sales momentum a few times in the last several years, and every time I've pointed out Switch's overall more than solid release schedule from first and third parties which will prevent sales from having a massive decline. In 2019 you doubted that Switch could pass 100m, later you doubted that Switch could pass the PS4, then 140m would have been too much of an ask in your mind. You know my argument already, so my response to the first half of your post can be condensed to me saying that the same logic will continue to hold true.

Switch is on pace to exceed Nintendo's projected 141.1m LTD mark by March 2024 and they'll likely forecast a figure of ~11m units for the fiscal year ending March 2025, because Switch's successor will hardly have an impact in the upcoming fiscal year. That's a decline of ~30% after FY23 declined by only ~15%. That will put Switch's LTD by March 2025 at 152m; the DS's lifetime figure stands at 154.02m. An additional mere 2m after an 11m year aren't a challenge, so I don't need to go into detail for each region. Try to run a shipment forecast for yourself and you should realize how hard it is to keep Switch below the DS in lifetime sales.