Last system they had to peak in their fourth fiscal year was the DS.  It launched holiday 2004 and 3DS launched spring 2011, so that is approx. 6.5 years.  I think this move actually cut into the legs of the DS, but they also had to worry about staggering the release of home and handheld systems at the time, so I can see why they did it.  

Now Nintendo is in a similar situation, but this time they don't have to worry about balancing home and handheld resources during a console transition.  So the very earliest would be a holiday 2023 release, but I think holiday 2024 is even more likely.  There is no point in releasing a successor if sales are still fairly high.

Dang big milestones for Switch coming up. RFA hits 1 million! That thing is just gonna keep selling, they better be coming out with another Ring Fit game this Fall. MK8 two weeks from finally hitting 3 million. AC probably three weeks from hitting 5 million. And Switch sweeps the top 10!

SMM2 and FFVIIR are in a dead heat. Which will hit 1 million first?

I don't think RFA needs a sequel just a year later; the first hasn't even been able to hit its stride due to supply constraints, it'll be an evergreen seller for years to come.

Well yeah sales-wise that is absolutely true.

But to me it seems Nintendo should take advantage of their popular exercise hardware. Ring Fit is different than a normal franchise game where you don't want to cannibalize sales. People are clearly enjoying Ring Fit and there is no reason to hold RF back to only one game for a long time. Nintendo should embrace that and expand Ring Fit offerings. I don't see any reason why they shouldn't come out with an annual Ring Fit release. There are tons of options for more Ring Fit games since it is an IP that uses fitness as the means to control a normal-type genre, it's not a straight up fitness game like Wii Fit. They could release a RF game in a different genre each year. I think it would be a huge missed opportunity for them to not seize on RF's popularity and end up only releasing a couple RF games all told. People already paid extra for the RF hardware, I think most people would be disappointed if they weren't given plenty more opportunities to use that hardware they paid extra for and only had a single fitness game to play for years. For example: RF Fight (2020), RF Action (2021), RF Flight (2022), RF Racing (2023), RF Rhythm (2024), RF Adventure 2 (2025), etc - assuming they keep it going into Switch 2. No reason to not do this. Also it'd be an easy pickup for a Switch 2 launch title to release a compilation RF of all the original Switch RF games. Whenever you release extra hardware that is popular you should capitalize on that and reward consumers who paid that extra money by giving them more opportunities to use that hardware, it's a win-win for Nintendo and consumers.

In a few years instead of just having one evergreen RF game they could have several evergreen RF games all with multi-million sales. And while RFA is a decent game as far as fitness games go, maybe they totally hit it out of the park with a different RF game that Switch owners goes crazy for and it blows away RFA sales.

Now yeah they totally need to scale up production, especially if more RF games come out, I can't imagine why they haven't. I can only think it's that they are being super conservative and still aren't sure of RF's long term success, but if anything a new RF game this Fall would give them even more of a reason to do what they should already be doing and scale up production of RF.

Yea no tbh i think Ring fit will get DLC or new free updates since the game is blowing up. No need to do multiple ones cause i really don't think it has potential to be a franchise so quickly. I mean the game is quite expensive and people don't seem to be tired of it already. I do think maybe this can become a thing they use as an argument for next gen.

And for the Switch cycle, we will have too see but we know Nintendo are planning to have a really long life cycle for it, it has been said. The DS got cut short cause they were scared of the new PSP coming out. Now with no competition in the handheld departement they don't really have to fear, and the home console departement is less of a competition for them. So i think we won't see a new console until sales really start fading away. But with only 1 system, i also don't think they will wait till it does like 6 millions a year either. So maybe end of 2023 or March 2024.

Nintendo need a AAA 2D Mario. 

It already has a “new” 2D Mario on it......

I don't think it will fall off a cliff, just that it will have a normal decline, with this year most likely being its peak year, and that by 2023 it'll be time for its successor.

Ideally, you don't want to wait too long or until your system is already dead before replacing it.

3DS sold 9.7 million in 2014, and you expect 2020 to be Switch's peak year, which means 19.4 million at minimum.

If switch is doing +100% over 3DS in its fourth year, why would it be +0% in its seventh?

Okay it'll probably be a bit higher, (though 3DS actually had a fairly decent 2016 didn't it, how much did it sell that year?) but by then Nintendo's big system sellers will have long since all released and it'll be pretty much cruising on evergreens and small/mid tier releases plus sequels that won't be system sellers the way their first Switch entries were.