This feel like a broken record now. Let time once again tell who is wrong

I've said it before, the whole narrative of Switch falling off a cliff once PS5/XSX come out is basically like saying "when the new model of luxury sports car comes out, nobody will buy motorbikes anymore."

The only possible big problem could be Ninty dealing with NS success like it did with Wii, killing it too early, partially tarnishing the Wii brand itself and so adding another problem to any flaw Wii U could have by itself. As Ninty tipically has little market overlapping with competitors, releasing next consoles not aligned with Sony and MS ones shouldn't be a problem at all, just like it wasn't for NS.
SW support isn't, either, RAM size gap between NS and PS4 and XBOne is not terrible as Wii U one was, sure, it will be with next gen, but games development starts typically one or more years before launch, moreover, third parties will need to support current gen at least until next will have a user base large enough, and many devs and publishers will still consider the old market attractive and profitable enough even for some time after next gen will have become the main SW seller, so, really, SW support won't be a problem. Not to mention that starting later and going very strong right now, NS most surely won't start declining soon. BTW it has no real competition in the hybrid market, and even choosing just Zen 2 based custom CPU cores, it will take years for Sony and MS to be able to make a possible hybrid version of their next gen consoles, while making hybrid version of their current ones would be half-baked and too little, too late anyway for their typical power-hungry target.

Nintendo is going to be laughing all the way to the bank when they have the top selling console for the next couple years...

PS4 didn't see peak sales until it had the Slim model for $300 in 2016

https://www.sie.com/en/corporate/data.html

https://vgsales.fandom.com/wiki/Price_cuts

Anyone that thinks that a $400-$500 console is going to effect the sales of the Switch chooses to ignore historical trends.  Most "next gen" consoles don't see peak sales until they have a price cut and a larger library of games to choose from.