Recently Nintendo said that Switch's successor will have to be something new. While that can be interpreted as Nintendo being up to something stupid, it's equally possible that this means that Nintendo is aiming for Switch to be an iterative platform, meaning that its lifecycle before replacement is supposed to go far beyond conventional norms of six to seven years for successful consoles.
An iterative platform would mean that Nintendo launches major revisions about every four years where first and third party developers alike can decide which iterations of the Switch platform can run their games. This is most comparable to the Game Boy and Game Boy Color relationship where the Color revision eventually turned into a quasi-successor. However, development priority isn't going to see such a drastic shift on Switch, because the magnitude of going from black and white games to colorful games is much, much greater than whatever a Switch revision can pull off.
The interesting thing about Switch is that it could get multiple such revisions. What we'll probably see later this year won't be something unusual, because for the concept of the iterative platform to be really confirmed, we'd need another major Switch revision in late 2024 or 2025. Only then would the typical generational cycle be abolished, because Switch in 2017 and Switch Plus in 2021 followed by Switch 2 in 2024 or 2025 would be keeping the status quo.
That being said, it should now provide an idea how Switch can cross the 200m mark, because with a traditional lifecycle it is very difficult to line up realistic numbers and end up with such a high figure. But if we began talking about Switch being Nintendo's main platform for 10+ years, we'd be able to spread out a 200m tally much easier across all the individual years.
As for the reason why Nintendo would break away from the traditional cycle, it might just be for the same reason why the separation between home consoles and handheld consoles has been abolished. Technology made it feasible to have a 2-in-1 device, so why should technology continue to determine the launch of entirely new consoles? It's something that people stick to because that's how it is without giving it any further thought. It's simply accepted that it is how it is.
Console generations became a thing in the first place because technology evolved and resulted in new opportunities for gameplay, so new generations weren't just about better graphics and sound for old concepts. But now that we are at a point where there should be virtually universal agreement that more processing power won't provide any leaps in gameplay anymore, why should it still be necessary to make that hard cut from one console generation to the next? That might be what Nintendo is considering, that they won't have to start with an installed base from scratch again if they make improved use of the already established practice of console revisions and take it a bit further.
I am running out of time right now, so I'll end my post here. But there's of course more to discuss regarding this idea.
Iterations are the way to go, IMO, and Nintendo has been hinting toward it since the era of Iwata.
Nintendo is on the right path with ARM chips, they have become incredibly versatile in the last few years (Switch is part of proving that). I also think it's the future of gaming consoles as a whole, while Xbox and PS5 are X86, there's a high chance PS6 and Xbox Series Y/THREE/363/whatever will be ARM.
I describe myself as a little dose of toxic masculinity.