Are you sure? It is the same with every Nintendo console, 3rd-parties are cautious to support it. And while Nintendo has their breakout successes which also help 3rd-parties (Just Dance anyone), they also have their stinkers like WiiU. So I am confident, that the Nintendo circle will continue - a new console will lacking pretty much any 3rd-party content at start.

Something not talked about shipments!!

First off I’m predicting 40mil in japan, for this to happen we need 2021/2022 to have huge years. Like a whopping 7.5mil-8mil one for 2021. Let’s begin....

NSW 2020 shipments (CY)

Q1: 1020k
Q2: 1150k
Q3: 1580k
Q4: 2710k
Tot: 6440k
LTD: 18.88mil

—> 3DS: 25.18mil (6.30mil away)
—> DS: 32.99mil (14.11mil away)

nsw 2020 is the 3rd best year for shipments....

DS06: 8730k >>>  DS07: 7230k >>> NSW20 6440k >>> 3DS12 6220k

Edit: this is the year to beat DS07 as DS06 is almost impossible!

DS07 breakdown

Q1: 1590k (biggest Q1 ever)

Q2: 2090k (2nd biggest and NSW20 1150k was 3rd biggest)

Q3: 1600k

Q4: 1950k

tot: 7230k

.....

...

We'll see, although I remain sceptical.

Indeed, we got Mass Effect, Batman Arkham, Assassin's Creed, Darksiders, and other games between 2012 and 2013, that was great

Yeah, I mean Switch 2 is numerous years away, but yeah hopefully by then Japanese third parties (and, well, just third parties in general) are ready to bring out big games on Switch 2 starting from launch, rather than having to wait 4 years to see the very first brand new AAA third party game

DQXII should come out in a couple years or so. Hopefully there will be more brand new AAA third parties games on Switch before then, but that is another obvious mega selling Japanese game that should come new, though likely not exclusive, on the Switch and once again show third parties that if you actually make games for the Switch you'll make lots of money.

Without any competition in Japan, it's fairly ease to envision continued support for Nintendo's next console.
Sony needs to do it's best to get third parties on-board with the PS5 but it's a chicken versus the egg situation, since there is basically no momentum without constant software releases and third parties aren't really in a rush to support a platform without constant software performance.

Dragon Quest 12 should by all common sense measures be a lock for Switch, though part of me expects Sony to moneyhat it to try to make PS5 relevant in Japan.

The problem with Sony money hatting Dragon Quest is that it only really moves consoles in the Japanese market and Sony isn't really invested in the Japanese market these days, it's why Studio Japan was significantly shrunk.

Hell, I can see Nintendo being the ones to money-hat it, especially if they promise to help with the localization to make it a worldwide release.

Pretty sure they would have already tried to moneyhat DQ only problem is SE don't control the franchise it belongs solely to Horii himself. This is why the series is on Nintendo platforms right now as Horii isn't interested in being moneyhatted he wants to hit the largest user base possible, at this point any moneyhatting would be purely for a non switch version to even exist he would have also seen FF's decline in Japan and realize any deal to make him break his rule is not viable as DQ doesn't have the luxury of high Western sales.

This isn't really true though. Japan studios have not had a  hit in japan for decades, sonys western studios have actually had bigger success' (TLOU/Spiderman/Horizon/GOT). Japan and japanese games are still important for sony, but they're not interested in making it in house. Dragon Quest is not a huge seller in the west but it is a good seller. Establishing Playstation as the place to be for JRPGS can really sway millions of consoles and 10s of millions in software, so its not trivial.

But I agree with your later point that its equally likely (if not more so) that Nintendo money hats it and does a localisation/publishing effort as they have done for several SE games in the past including DQ9 (publishing & marketing it in the west)