--- Also known as DS level sales
--- It really wasn't, 2017/18 was PS4 peak years at 18-20m as you say, but middle of the year sales were around 250k with spikes to 350k, Switch has only dropped below 350k 1-week in the last 15 months. I'm sure PS5+XBS being more available will affect Switch sales a little as new hardware is more attractive than old, but I don't think it's significant.
--- 3DS sales drop caused by PS4+XBO availability!? um ok. Again I'm sure some people might have bought 3DS on a whim when they couldn't find PS4, & maybe some other people decided against buying a 3DS once they got a PS4 but the numbers are probably in the 1 or 2-digit thousand range at best, sure i'm pulling that estimate out of my ass but do you really believe PS4/XBO were the major cause of 3DS's 2013/14 sales drop?
--- I think you are being optimistic on the stock situation here, I doubt they will be widely available this year at all (except maybe the XBS|S)... and massively pessimistic on the effect it will have on the Switch, you think 40% of Switch's current sales are from people who can't find a PS5/XBS?
--- OLED model will increase weekly sales (the new + shiny effect) but given the earlier pro rumours it might only counter the sales slowdown caused by those who were waiting for an improved pro model. However given the current level of sales 25M is the minimum it will manage this year even if OLED gives no gains... lets look at the last 3 years sales from July-Dec: It did ~11.5M in 2018, ~13.5M in 2019 & ~17.5M in 2020. The Switch is still tracking ahead of where it was this time last year.
--- To finish the year at only 100M Switch will have to drop to weekly average sales the same as it was in 2018, which was under 200k in non holiday weeks
--- This is at least sensible, given the lack of a pro model it's more likely Switch successor will be in 2023, and once a launch is announced sales will fall, you just seem to be assuming an unprecedented quick fall in sales at least a year in advance of normal though.
--- In 2018 it was more like 200-250k at this point in the year. But lets translate the PS4 slowdown rate as if 2018 = now for Switch. PS4 sold 7m in first half of that year, which was 38% of the yearly sales, Switch has sold >10.5M in first half, if that's 38% then this years sales should be >27.5M (LTD 104.5M). Then the next 2 years PS4 sales fell by 22% & then 40%, so Switch following the same pattern would mean sales of 21.5M & 12.9M.
Of course you mention PS4 death wasn't the biggest, the DS is the fastest falling we have VGC data for if we use 2009 as the end of it's peak period, which fell by 25% & 57%. But this would still result in sales of >20M in 2022 & 9M in 2023 if plugged into Switch's current sales.
--- below 130M is frankly a pessimists dream for Switch at this point.
DS sales were more like 450-500K per week most of the time. Far ahead of switch sales are now.
I am not saying Switch have gotten below 350K, however it is lower than last year and lower than sales were this year earlier and it's not once but for several weeks now. This is some indication that the sales are not going up but down. And they will reach probably around 300K per week by end of August.
The 3DS and every console for that matter are slowing their sales once new (if successful) console is launched because there is new thing in town and the potential buyers now have more options. Whereas before that the only other options the buyer had was PS4 and XB1, which almost all of the gamers have already bought by 2020 for comparison. And this is taking effect not only for 3DS in 2014 or Switch soon once the stock become more available but for every other console too. I guarantee you that if Switch wasn't released PS4 would sell at least 10-15M more in the last 3-4 years, than it actually sold. XB1 maybe around 2-3M more.
And the slow of the sales will not be only because of this, but this will drop it by around 15-20%. The saturation point will help to drop it at least by another 10-15%. And when the things combined switch will be selling at around 200K per week (non holiday) for most of the next year.
OLED model will do little to no effect for the sales, cuz why ? only because of some more colors on the screen people will sell their systems and buy new ones ?
This is like announcing the XBOX One S Gears of War RED limited console in 2016 with the 2TB storage, Or PS4 Pro 500M edition with 2TB and special controller.
Switch doesn't need to drop like 2018 levels. It is dropping to 300k next month, and the holiday season will be something like 2018. Strong but not as much as 2019 or 2020. 14M In 6 months is not bad. I don't know why you are saying is minimum. It is perfectly respectable number. It can do 4M till september and 10M for the last 3 months of the year which will be very good number.
Once the successor is announced the sales will fall yes. But probably will be announced in january 2023, for the launch to take place at march or april just like the Switch. So yes, the full year will be affected. But even if the announcement camed later it still would affeact sales immediately, because everyone will wait for the new system.
And I am not comparing PS4 numbers to Switch numbers, I am comparing just how well PS4 was going and how everyone believed that it will reach at least 130M and most of the people even believed it can reach 140-150M but it won't reach even 120M. Now is the same for the switch, everything looks very good but just like PS4 and many other consoles, it comes point when in period of just 2 Years the sales drop of a cliff, just like Wii, DS, PS4, and many more. And the example with PS4 was not for 2018, but for 2019, and not the pure numbers but the drops. From 14M to 8M next year to 2M this year. Just like many other consoles experienced this so will the switch. And this drop may begin starting next year.
And The PS4 death is infact the biggest one. from 14M to 8M to 2M this year. The slight drop years like 2018 doesn't count. as it was for example the 27M year for the DS after it's 29M year. It counts from the first medium drop to the end. Switch will do the same. 25M now, slightly weaker than last year, and next year somewhere around 15M to under 10M in 2023 (possibly 6-8M), and 1-2M in 2024.
Also you are talking about how switch is having it's best year yet, passing even last year until this point in time. It is passing it because of it's first quarter of the calendar year. it's second is much lower, with the next week numbers it will make around 5M for the quarter where as the last year it was 6M, that also shows how switch is selling less and less with the time passing. PS4 in 2018 was the same. First quarter was stronger than 2017 first, and the system was up YOY, however the next 3 quarters were weaker and it sold 2M less than 2017 overall. Just like it's gonna happen with Switch. Its lead is from the first 3 months. It is 1M behind the second quarter and probably will make around 2-3M less in the next 2 quarters leaving it at about 25M this year.
And another comparison. PS4 was also ahead of PS2 sales back in 2019. When everyone still though PS4 can reach PS2 numbers or at least 140M lifetime.
Well it didn't happen. And the situation with the switch is the same here. That is what I am trying to tell. Just because something is looking very likely and just you think that there is no way of it to not happen, it shows you that it won't happen. Just like the PS4 situation turned out after 2019. It is okay to think it have a chance for the switch, however don't be 100% sure. You can't be sure of anything. The PS4 situation is proof that the situation can look very very good and in the end when the cliff come all dreams are being broken.