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