I just don't see Nintendo only having one console product at a time. They are going to want some kind of lower cost 2DS equivalent. I am fairly sure we will see another 3DS revision at some point.

For some reason that made me laugh. What would the Switch equivalent 2DS be? Just a screen with joysticks you can take with you, but can't remove the joycons? Basically a PSP? I guess it can doesn't switch that much, but you can take it on the go? Nintendo Go. Hold on, calling Nintendo...

I think the writing is on the wall that it's a replacement. Nintendo isn't saying that, of course Nintendo isn't saying that, they still want people to buy the 3DS since it's out on the market now. Only a foolish company would ever make such an admission. One way or the other Nintendo is gonna roll the dice with this.

Pillars just like the GBA and DS.

Given that the Switch is now a portable device as well I will assume that the 3DS will be replaced in the few short years as it wouldn't make much sense to support two portable devices simultaneously. Any new 3rd party games that would come to the 3DS after the Switch launches will most likely be a port of the Switch version with no real second screen functionality to make use of the 3DS. Since I upgraded my 3DS XL to a New 3DS I definitely find playing games in 3D a bit more appealing as the screen's 3D effect doesn't jitter by slight movement anymore so consider that if you want a New 3DS.