Since this has previously been a topic of discussion here in various threads, I thought I would bring this point up from the last Nintendo investor Q&A

Question: Nintendo Switch was announced under the development codename “NX” in March 2015,
and then the official name was announced in October 2016 prior to its launch in March
2017. Looking back, do you consider this a success in terms of hardware marketing, given
there was a space of about two years between the initial announcement and launch? Do
you think a similar interval between the announcement and launch of a next-generation
platform will be necessary?

We will provide information about hardware and software at the appropriate time for
each product and strive to reach a wide range of consumers.

So basically what I said ... they only announced NX so early (2015) because they were making an announcement for smart phone games and wanted to reassure investors that they were not getting out of the console business. 

As such it was a special case to announce NX that early and (by logical extension) does not mean Nintendo has to announce the Switch 2 on the same time line. Likely if Switch 2 is a 2024 product, they can just announce it in 2024 and launch 4-5 months later if they want (that was the actual length of the real Switch marketing cycle last time).  

Yeah, but it was fun/frustrating that year and a half of speculating and rumors of what NX was going to be. The one constant is that is was going to be a hybrid device. Tho we had rumors of the dock adding horsepower. Someone made a 3D-printed oval-shaped thing that always looked fake to me (esp when the image was a badly cropped UE4 demo and the thumbsticks were molded in).

I am ready for a new Switch even if just so my old games run a little better.

Yeah of course this time around the last thing they want to do is have 130-140 million users stop buying games in anticipation of the next system.

If Switch 2 launches mid-next year we will probably hear about it in the first couple months of the year. If it launches holiday 2024 we'll probably hear about it late Spring or early Summer 2024.

Nintendo has never before had a system so popular that it was breaking software sales records like Spat3, Poke V/S, TotK this late in its lifecycle. Usually at this point people are ready to move on, but instead you've got an enormous userbase rabid for more great Nintendo games on Switch. They need to do everything they can to try to seamlessly transition into next gen, getting Switch owners to hop on board, while at the same time not cutting off the massive software sales the Switch is still getting this late in the game by announcing a successor too long before its launch.

I think Nintendo learned from their Wii U reveal mistake, when they only showed the gamepad and didn't mention the console. That's why they wanted to be sure that there won't be another misunderstanding with the announcement of their smartphone games ambitions. IMO it was the right decision to mention NX at that point.

Otherwise there would have been rumors that Nintendo could leave the traditional console market after the obvious massive flop of Wii U at that point and the fact that 3DS sales wouldn't come close to DS sales due to mobile games.

Currently Nintendo sells more games than during Switch's first 3 years. Hardware sales decline, but overall Switch is still very profitable. I expect the announcement of a Switch successor in May/June 2024 and a release in November, just like Sony did it with PS5. Otherwise Nintendo would hurt their holidays 2023 sales. If they would announce the Switch successor early 2024 they would also anger customers who bought a Switch during holidays 2023.

It was pretty obvious that it was a special case, but nice to get it confirmed.
The Wii U tanked. Even as arrogant as Nintendo is, I'm pretty sure after the end of the calendar year of 2014, they knew it had become a large liability. Mario Kart 8 and Super Smash Bros for Wii U weren't enough to turn it around. The 3DS was successful, but far below the DS, below the Game Boy Advance, and below the Game Boy/Game Boy Color.
With all that in mind, they wanted to assure the world that they weren't sticking with the Wii U through 2017 and 2018. I doubt announcing the NX as a mystery platform (home console? hybrid?) had much of an impact on Wii U sales.

Nintendo could theoretically announce/debut Switch 2 in say first week of March 2024 (thus limiting the impact on Switch 1 sales for the fiscal year) and launch by say late June 2024 and it would have the same marketing cycle length as the original Switch did.

I would say if they are launching in 2024, that would probably be the smarter course of action, all this "well they have to announce in 2023" to me doesn't make a whole lot of sense, why kill any more Switch 1 sales going into a holiday season for now great reason. Switch 1's marketing cycle really was only actually a little over 4 months (late October-March 4th).

Yep, Switch reveal trailer was October 20, the presentation was Jan 13 and it launched March 3. This is also a similar time frame as PS5 reveal to launch. With how fast information travels these days, it really isn’t necessary to have more than a 6 month reveal to launch.

Yeah exactly. Obviously they aren't announcing anything in 2023. I don't even know why some people bring that up as an option. Unless Switch was dying already (instead of breaking SW sales records and still competing for the best HW sales right now) then things would be different but there is no reason to cut Switch sales off at all, certainly not for the holiday season.

Now in terms of what might actually happen, yeah I would expect 6 months lead time at absolute most from announcement of the system to release. Either early year announcement and June-ish release (when kids are getting out of school), or Summer announcement and November release. Probably more like four months from announcement to launch because they really want to not cut off Switch sales and momentum too long before the next gen ships.

After the failure of the WiiU, they couldn't just announce they were entering the mobile space without also saying they weren't exiting the console market. How many would have assumed they would be exiting the market otherwise?

Exactly, I've tried to explain this a couple of times here to some posters but it's always been met by "yada yada  yada, they have to announce Switch 2 now because NX was announced two years before launch!" ... so it's nice to have Furukawa actually just confirm what should have been obvious (but apparently wasn't to some).