Except for Dragon Quest and Monster Hunter World, what does Playstation have left in the future that Japan really cares about?  And I believe that at least one of those 2 will be on Switch 2 as well.  So, even accounting for all of the exports I can only entertain the PS5 crossing the 10m mark in Japan at some point, and even then, not by much in my opinion.  And there's a pretty large gap between 10m+ and almost 13m.

The data is great: The conclusion is optimistic. Once Switch successor hits the market, PlayStation will hit a hard wall in terms of Japanese sales figures. For that, I believe your 2024/2025/2026/… estimates need be lowered 0.5-1.0mil. Furthermore, once PS6 drops, PS5 sales figures will fall off a cliff: 2029/2030/2031/2032/2033 need be adjusted with a “max sales ceiling” of 0.4mil for any one of those years. It’s not out of the realm of possibility to see PS5 have legs lasting into its successors lifecycle…but something would need to go wrong with the PS6 in order for this to happen (eg PS6 is overpriced like the PS3, there need be a supply shock similar to with the PS5, etc).

In all, I think your estimate would more appropriately be knocked down to around 7-8mil sales remaining in Japan, which really leaves the initial question unanswered as to whether PS5 could surpass the Wii in Japan.

I agree with both of your statements. What the PS5 will sell in Japan, have to be now till the Switch successor launches there, cuz it will eat big chunk of those PS5 sales. Just like I said before (when the PS5/XBSX launched and had stock issues) the console sales overlap when there is competition. Sure Switch isn't directly competitor to PS or Xbox, but still it has taken some of their sales when they haven't been available freely everywhere. The same of course goes for the opposite. PS5/Xbox too eat up some of the potential Switch sales. If there were no PS/Xbox Switch would have break 150M by now. And the opposite, if there were no Switch PS4 decline would be steeper and would've sold more units. PS5, Xbox too. In Japan xbox is not factor, but the PS5 surely has taken some of the Switch sales and vice versa. Worldwide of course PS5 will fall of a cliff once PS6 launches, so better be selling now when it's the major Sony's console. But there is still much time. It has around 5 years more where it's the main focus for both Sony, and customers.

I disagree. The year Switch released was PlayStation 4's strongest year in Japan. Nintendo and Sony consoles do not harm each others sales substantially even in Japan.

It may or it may not, but does it really matter as it will be a hollow victory with all the exports to China.

(I included these quotes above because they pertain to this whole topic)
Oh my, I totally forgot about Nintendo's next console. Whoops haha.
Hmmm. Ok. I need to do some thought and research
Mar 2016-Feb 2017 PS4 sold just below 2.12M in Japan (2,117,036)
The Switch released and from Mar 2017-Feb 2018 PS4 sold 2.02M (2,020,471)

Oh, hmmm, I thought that would cause a bigger drop since it was competing with the Switch. I did notice that 2018 Jan and Feb sold way better than 2017 Jan and Feb, what game came out to boost the sales. I'm seeing Destiny 2 and Resident Evil 7 for December (more Western related, hence not a big spike for December 2017). Monster Hunter World, Street Fighter V, God of War, and Red Dead Redemption 2 for January (2 Japanese related games, and 2 BIG Western games). February had Metal Gear Survive (A Japanese-related game). Ok I see why there was a bigger spike in Jan and Feb now, they had better Japanese games than 2017 Jan & Feb, Kingdom Heart HD 2.8 Cloud Version, Double Dragon IV, & small indie-like developers. Lets check the next year.

Mar 2018-Feb 2019 for PS4 sold 1.43M (1,432,677)
Sorry for the weird comparison months, I just wanted to put Switch and PS4 head-to-head to see if there was any direct difference between the years.

Okay looking at this I see that the PS4 had a decline of -5%, then a decline of -30%. So, I think PS4 took a hit once Switch became popular.
Now lets take a look at PS4 the year before PS5, and the year of PS5
Nov 2019-Oct 2020 PS4 sold just below 0.78M (779,695)
Nov 2020-Oct 2021 PS4 sold just below 0.15M (148,857)
Once PS5 entered the ring PS4 took a -80.7% decline, ouch.

Alright I understand why you said what you said @firebush03 .

It looks somewhat that Nintendo does compete with Sony in Japan. (Not related to this forum, but it makes sense, Sony is focusing on America and Europe, while Nintendo is focusing on America and Japan, or so it seems).

Ok I will recalibrate my guestimates. Once Nintendo's next console releases PS5 will drop ~-30%, and from then on will drop ~-10% to -20% (I'll stick with -10% for optimistic-ness). Then once the PS6 launches we should see something like the -80% drop (I'll stick with -80%) and from then on will drop -30% with each succession. For trend on how long it will sell into the PS6 life I will use info regarding PS3 and PS4 (PS2 was a beast haha), PS3 was no longer selling in Japan after Dec 2017, so 4 years into the PS4 life. PS4 is still selling in Japan to this day, so 3 years into the PS5 life. I'll make the assumption of 4 years for the PS5 selling into the PS6 life.:

PS5 is at 4.75M + 2.3M (2024, Rumored release date of the next Nintendo Console) + 1.61M (2025) + 1.30M (2026) + 1.17M (2027) + 1.05M (2028 rumored PS6 release date) + 0.21M (2029) + 0.15M (2030) + 0.10M (2031) + 0.07M (2032) = 12.71M

If Sony decides to accept Monster Hunter, Dragon Quest, Final Fantasy, Kingdom Hearts, and Metal Gear (either remakes, ports, or new additions to those series) in the latter years of the PS5 then we should see some increased console selling, like Jan and Feb of 2018.

So if the 12.71M estimate comes to fruition (based on optimism and realistic past data) then...
NO the PS5 will not overcome the Wii's total of 12.77M. Even being an optimist with -10% and -30% estimations.

Well, I personally don't think it matters if they export to China because they are still "sold" in Japan. (I might be correct that they are sold in Japan and then exported, thats just what I understand from the exporting conversation).

Of course.