Spring 2025 earliest.

I believe a

- New model (maybe two)
- Price drop

will both happen before a new Nintendo system is released

Spring 2025

March 2024.
The supply chain issues, and overall home run success of the Switch will give it a little less from 2 years from now before being replaced.
7 years will be one of the longest gaps ever between a Nintendo platform's launch and its successor. With the Switch, it makes sense. It's the best-selling Nintendo home console of all-time and will probably give the DS a run for its money even if it doesn't reach or exceed it.
Nintendo could go super bold and do a Game Boy Color situation. They could launch a Switch Pro or Switch 4K between March 2024 and March 2025. Then they could launch a Switch 2 between November 2027 - November 2028. I do not think this will happen, but I bring it up as a possibility.

Spring 2023 is my vote. I think this date is most likely based on Nintendo’s comments.

• Consoles are planned years in advance, as Furukawa has stated, not developed and saved for when it seems like a good time to launch. It makes little sense for developers to create software intended to launch the console only to sit on it, as that creates huge gaps in their schedules.
• Furukawa announced in January 2020 was the midway point of the Switch’s lifecycle which indicates they were looking at a late 2022 release date back then. Although, he said similar comments through 2020 and 2021. This doesn’t necessarily mean anything for Switch 2 since consoles can exist at the same time - for example: PS2 had a 10 year lifecycle, the last 3-4 years were alongside PS3.
• Furukawa also said they were breaking tradition. This could mean multiple things, but I think he means Switch 1 and 2 will run in parallel for some time rather than Nintendo’s traditional slash and burn the previous generation to make way for the new one. Why? Nintendo ran a little experiment with 3DS, seeing what would happen if they supported the 3DS during the Switch; sales went up year over year.
• Furukawa said that Switch 2 would expand the ecosystem they built with the Switch. This indicates that rather than starting from scratch on the next platform, there will be continuity. This is how it works on most other platforms: iOS, MacOS, Windows, etc… Another supporting point is Nintendo is not likely using a drastically different hardware or interface for the next generation Switch given their deal with Nvidia.
• The odd Breath of the Wild 2 delay to “Spring 2023” is a smoking gun. Zelda, particularly Breath of the Wild, is Nintendo’s flagship franchise. It is the ideal game to launch Switch 2 with. The game has been in development a very long time and is unlikely to have had the same developmental hurdles of Breath of the Wild 1 based on what we know. Even with Corona, it shouldn’t have this extensive a decade cycle. What is the reason? Simply polishing it up isn’t a great reason to miss the holiday season since polish can be applied after launch with updates (like with the first game). A Switch 2 release time would be a reason.
• When asked if Switch 2 was launching this 2023 fiscal year, rather than the usual unambiguous “no” Furukawa dropped the classic “No comment” line. For those unfamiliar with the tech industry from at least the 1980s to early 2000s “no comment” translates to “Probably, but we’re not ready to make an announcement on this yet.”

So, based on their comments, I think a Spring 2023 release seems most likely, Summer 2023 (maybe late winter in case Nintendo decides a little earlier in March or something) second most likely, and so on. And there are some other things that can be gleaned from the info. Switch 1 won’t be killed off before as has been Nintendo’s general (bad) strategy before this time. Switch 1 will expand the lower tier while Switch 2 will take the upper tier and play all Switch 1 games - perhaps with higher settings for those devs who wish to update: many games on Switch already have those capabilities given they were ported from other platforms with multiple tiers (both hardware and OS).

I'm still sticking to holiday ('fall') 2024 for now.

Spring 2025 makes the most sense to me. I don't think they've gonna cut Switch out of the picture as soon as a lot of people seem to think, but I also don't think they can afford to wait literally any later than that for a successor, so it seems like the sweet spot. Holiday 2024 is possible as well though.

March 2024

But we still have supporters claiming 2027 and beyond or that the current system will receive price cuts, despite inflation and shortages.

March 2023

November 2024 I guess. This year Switch sales are still above PS5/XSX. Next year Switch baseline should be around 200k or slightly below and on par with PS5/XSX. In 2024 Switch baseline should be between 100 - 120k, which is still pretty good for its 7th year. I think there's no need to rush a console release this time.

Nintendo knows that a new console launch is a bit risky, especially as long as the hardware supply is limited. So I think they try to play safe with Switch as long as they can.

I agree that the delay could be a smoking gun, but not for the reason you think it is. I think it has nothing to do with making BOTW 2 a cross-gen game (like TP and BOTW). I think it's because 2022 is such a packed year for the Switch. There are so many Nintendo titles, a Nintendo holiday title (Pokemon Gen 9), and tons of third-party games. 

I think there's at least a modest chance Nintendo is taking the gamble of delaying BOTW 2 just so that 2022 is slightly less packed and so they have a massive title in the first quarter or at least first half of 2023. 

I found out recently (thanks to a user on here) that Nintendo could've had Super Mario Odyssey ready to go at Switch's launch in March 2017. But they sat on it all the way until late October 2017. I'm glad I didn't know that then, or I would've been salty waiting so long. 

So it's happened at least once where Nintendo had a massive title ready to go and sat on it for about half a year or more. It's very rare, but it's possible. 

I would've said Spring 2023 when the Switch launched (or thought that way even into 2019). But with the supply chain crisis and the home run success of the Switch, I say March 2024. November 2023 is a possibility, but not as likely.