Planning for it, yes. But panicking and rushing onto a new system prematurely is a dreadful idea.

I never said the Switch Hardware would drop off due to their existing IPs already being on the platform, I said new games will do little do boost hardware. The Switch hardware dropping off is projected from other Nintendo hardware. Of course impossible to know exactly how the Switch will age but as time but what is the argument against a Switch 2 offsetting this (outside of, they can continue to sell Switch 1) because they can actually just do both. All the meanwhile benefitting from software which you complained about being missing a few months back. 

Yes there is, smart companies know what they're doing with their launch years ahead of time. 

A new product launch is now something you just pull out of your ass rolling out of bed in 2022 and saying "OK now we need to figure this out".

Games take 2 1/2-3 1/2 years to develop, they need to know by this fall at least what they are doing with Switch 2. 

Just because you are the consumer and you only see/play the finished product and its new to you is meaningless. That's true of basically all entertainment not just video games. You may have a good time at a movie, but you probably will never understand the thousands of hours, years, decades sometimes that goes into making that product. But just because you don't concern yourself with it doesn't mean it's somebody's job to do so. You need to be on top of that stuff years in advance as a company. If you're not you are extremely irresponsible as the president. 

You're arguing a point I never made. I never said they shouldn't be planning ahead for Switch 2. 

Again, there's a reason what you suggest hasn't been done to other successful systems in their 4th year. It's simply a bad idea. You'd be missing out on millions of potential Switch sales by replacing it prematurely, and millions of lost sales translate to hundreds of millions in lost income.

Well these decisions impact both systems. You kind of have to decide like now what Mario Kart 9 is and what system that will be on. You can't just say in 2022 "OK I thought about it and now I decided it should be a on X or Y", OK great, now the dev team needs 3 years to deliver the product. 

They need to know really now what they are launching the next system with. 

And lets be real almost every Nintendo system aside from the Virtual Boy has gotten minimum 4 years of software. Even the GBA still had new software coming through 2007. There's no scenario in which the Switch doesn't get a minimum 5 full years of software support, probably more likely you're talking 7 years. The 3DS had 6 primary years plus was supported by Nintendo with games for a year + beyond that, that's more than fine even for a successful platform. 

If you're going to whine at that point about there still not being enough to entice you to buy the system or not getting enough content after 6-7 years of software development, you're simply not a reasonable consumer and/or the product was never for you anyway. 

Again, you're arguing things I never said anything about. Show me where I said they shouldn't have a plan for next gen. Of course they should. 

It's not just having a "plan", actual software development needs to start to begin pretty soon here. A 3 year dev cycle factoring in some bumps along the way, you need to have actual game development underway like this summer/fall. And even that may be cutting it tight because Switch to Switch 2 is probably a generational leap whereas Wii U to Switch was basically the same tier hardware just a bit better in some respects. So you have to account developers needing a little more time to take full advantage of much better hardware than they had before. 

So for us as consumers while Switch 2 may be years away, for Nintendo it really needs to be top of mind like now. As a plan yes, but even as actual game development and staff being allocated to these projects. Games just aren't going to program and art design and level design themselves. 

What does any of this have to do with what I said though? I don't disagree, I just said replacing Switch in 2021 would be foolishly premature.

Not sure where you're getting "replace the Switch in 2021" from, don't think anyone even the OP has said that. A phased transition is something different. While I think there is some merit to it, Nintendo is prone to not being able to do even standard transitions very well, that they probably shouldn't try to get too cute. 

Plan for March 2023 Switch 2 launch and support the Switch through 2024, basically same as you did with the Switch and 3DS. Getting too fancy or cute might be doable but when you have so much trouble with transitionary periods, probably just better to keep it simple.