By all rights, Switch should have been/should be the 3DS successor, as much as the Wii U successor. Part of what appealed to me so much about the IDEA of Switch, even when it was just a rumor, as the idea of this so-called "hybrid console", that would bridge portable and home gaming. Home gaming you could take on the go.

And personally, part of the biggest appeal of that, to ME, was that it would mean you would no longer have to buy two separate consoles to have both functions. And thus, you also wouldn't have to feel compelled to buy both consoles, just to get games that were exclusive to ONLY one or the other. By all rights, Switch should be that system, and it should a console where ALL the games that would have traditionally come, separately, to say 3DS and Wii U, would ALL come out on just one unified platform now. You would only have to buy ONE system to get all those games from now on.

There is a TON of appeal to that idea, to me. And I feel like, personally, while Switch is doing really well, I think it could be doing EVEN better, if 3DS sales and new 3DS releases weren't still somewhat, arguably, eating into its potential sales. Yes, Switch needs better battery life to be a true portable, for sure. But otherwise....I'm personally just kind of over having both systems. I'd rather just have one system, that is both a portable and home unit at the same time, with all of the games of both.

The moment that Pokemon Lets Go and the 2019 game were greenlit was the same moment that killed any chance of a 3DS successor.

As if...Nintendo's "successor" consoles have always sold less than their predecessors. And not only that, but the 3DS is already a successor to the DS itself, they would not make a 2nd successor console, because it would most likely sell as half as much as the 3DS at best. Simply put, the 3DS and its offerings have run out of steam in the contemporary gaming industry. Smartphones are taking over, and if they were to make a 3DS successor, the only thing it would do better than the Switch is have a dual-screen and most likely be cheaper. But they can always create a Switch mini down the line.

Even from a western standpoint, support is much better than last year.

Payday 2, Outlast 1/2, N Sane Trilogy, Wolfenstein II, Paladins, Fortnite, FIFA, NBA 2K, Wasteland 2, Pillars of Eternity, ARK: Survival Evolved, Warframe, etc.

Yes as many above said... Nintendo Switch mini with no dock capability.

If Nintendo focuses on the Switch 100% with future devices (Switch Pro, Switch 2, etc) then no...there is no need to. It covers both handheld and console needs for Nintendo and a 3DS successor would be pointless and divide their resources to cover two devices that play games on the go.

If Nintendo releases a new home console alongside the PS5 and NextBox, then we already have one. The Switch would become the official 3DS successor and you would be able to play your portable games on your TV.

Honestly I can see Nintendo doing either one of these, and I am fine with whichever they choose between the two. Both are good strategies TBH.

Looking at Japan ytd hardware and software, there is a overall decrease in numbers, despite switch doing better.
At least Japan need a sub 200$ device, there is a demand for it there.
I think they are only waiting technology to shrink switch at reasonable price, add a random feature and rebrand as dedicated handheld, instead of calling it mini switch.

It would make little sense for a non switch 3ds successor.... so I'm expecting the announcement anytime now :)

Switch is actually up YoY in Japan. True, it's slightly down worldwide, but It's doing insanely well in its native land. A smaller iteration of the Switch is far more likely than a dedicated 3DS successor, which would undermine the entire point of the Switch to begin with. 

SWITCH DS (SDS) 2019