Not for $350. The only Tegra based SoC I know of that would be able to achieve that kind of power is the Xavier which isn't even out yet.  Even though I like the idea of staggered hardware generations like Soundwave has described (even advocated for it before we knew what the Switch was), I don't think that's the priority for Nintendo nor is it financially viable at the moment.  What they want to do is try to drop the price of the Switch to as close to $200 as possible by the end of next year because that will probably be the console's impulse purchase price point which will allow for multiple Switch units per household like Nintendo wants.

We don't know what Nvidia is really working on because the consumer class Tegra chips (ie: what would be basically the Tegra X3) is something Nvidia is likely not going to talk about anymore. Why? Because those chips are for one vendor now and one vendor only and that's Nintendo. And Nintendo would likely prefer they keep quiet, so Nvidia will understandably respect that. But I certainly think a Tegra X3 does exist (not just the giant sized Xavier chip for cars), Nvidia just can't announce it/show it because everyone and their grandma would know it's for a new Switch model and start flooding the internet with speculation. 

Likely Nvidia can make a chip for Nintendo comparable to the Apple A12X in the new iPad that just released. A12X is probably about 4x the Tegra X1 processor, but when the Tegra X1 launched it was comparable to the high end Apple chip of that time (Apple A9X). I don't think Nvidia has just been sitting around twiddling their thumbs. 

$200 is fine and dandy for a budget model, but I think people need to realize something ... price cuts and "kid friendly redesigns" never pushed the 3DS into sales shipments past 14 million/year. If Nintendo wants the bigger numbers for Switch (like 20 mill/year shipments) they're gonna have to understand the whole "kiddie portable" thing doesn't sell as many systems alone. Part of the Switch's appeal and a major part of it is being able to play fairly high end games ... at least keeping only a 1 generational gap. If Sony/MS move to PS5/XB2 and Nintendo is stuck with PS3/Wii U tier games, that's a two generation gap and the Switch becomes much less credible as a "portable console" and once they've used up most of their top tier franchises (probably around 2020), the system becomes a harder sell. 

I'm sorry but your post seems to contradict itself a bit. First you tell me I'm wrong in my assumption by citing the GBA and DS revisions, but then you go on saying that: "a simple "half gen upgrade for 4K TVs" isn't as compelling a sell as a Switch gen 2, Switch gen 3, etc... Especially when Switch 2 and 3 are serving an obvious demand with more power, longer battery life, and/or different sized screen", which is the same as saying that a Switch Pro won't be enough for consumers that will, instead, hope for a new console.

About the examples provided that did work, I won't comment on the GBA => GBA SP because I didn't follow the market as much then, but the DS to DS Lite is, sorry to say, bullsh!t. First of all, the original (and ugly) DS console was in the market for only a year and 4 months before being replaced by the same spec'ed DS Lite, the DS launched in November 2004 and the DS Lite came out in March 2006, and endeing production in 2007. It was the DS Lite model the one that was available through most of the life of the DS family, obviously being able to sell more units. And on top of that, the DS Lite was cheaper from the start, $150 vs $130, and took advantage of the launch of Pokemon Diamond and Pearl as well as the explosion of casual games like Brain Training and such.

There were a lot of other factors in place to make the DS Lite sell better than just being a new model, and the launch of he DSi Lite proved that.

The transition can be changed, some people are too entrenched with traditional "rules" as if none of them can be bent or broken. It reminds of discussions of the NX/Switch on this board too where you'd explain the hybrid concept and the person would say "yeah but how's the standalone home console NX supposed to work then?".

Just because you have a Switch Pro, and even if it can play some games the previous model cannot, doesn't mean the previous model is just immediately worthless and goes into the garbage.

You could have a situation for example for example you have 200 Switch games release in 2020 ... lets say 15 of those are Switch Pro only all from third parties. Only specific titles that can't possibly be ported to the older Switch ... Kingdom Hearts 3, current Call of Duty, RE2 Remake, etc. No Nintendo games are Switch Pro only. You still have 185 games coming to the OG Switch. In 2021, maybe that number increases a bit to 20-25 3rd party games only for Switch Pro. 2022, number ramps up again and maybe Nintendo makes their first Switch Pro only title then. That's fair IMO. 

And people upgrade their smartphone every year or two because they WANT to, not because they need to. The fact is today is not the 1980s anymore. People love to buy new stuff, it makes them feel good. Unboxing videos get millions of views. An iPhone 4 from six years ago can do most anything the new iPhone can, you don't *need* to have it, it's a want. And I'm pretty sure the XBox One X is the lead XBox SKU now, for PS4, the Pro is probably 30% of their sales, but that's very lucrative because they apparently make more money on the Pro model than the regular model.

Nintendo will want those revenue streams. The Switch is simply in a curious spot tech wise because if you double or triple the Switch chip like the PS4 Pro or XB1X, suddenly PS4 ports become much more doable, it's just right at the cut off point.

I also don't think going forward there will ever be just "one" Switch model once this new one arrives. There will always be two, one high end and one cheaper lower end, and it will keep cycling that way, the high end model will move down to the low end spot after 3 years or so with a new high end model taking the $300-$350 price point tier (which makes Nintendo more money). The 3DS currently is just a placeholder for the lower price Switch, once that is out, 3DS is phased out, but a new higher end Switch then takes over the top end spot.

^Erm... in your scenario, third parties will be the last ones to jump to Switch Pro only titles, not the first ones. And it won't be because they won't like the extra power, because it's obvious they would love it, but because of the lower install base. Unless of course you expect the Switch Pro to sell as much if not more than the regular (and by then cheaper) Switch, but we both know that this won't be the case.

Also, now that you mention the discussions before the revival of the Switch, weren't you the one saying that there would be several Switches of several dimensions to catter the smartphone and tablet users? Because that hasn't happened, unless you expect that Switch Pro to be the tablet like model.

The Switch already is a tablet like device. 

Nintendo could court 10-12 third party titles a year. They don't need every third party title, but you don't want to be missing too many of the top tier IP and what happens if the next Fortnite craze is something that requires a PS4/XB1 tier performance, you're shit outta luck then. If they could get Call of Duty, Kingdom Hearts, RE2 Remake, into the Switch ecosystem and a few others it would be worthwhile and those games are waiting for Switch owners any time they are ready to move on up rather than starting a library from 0 again. 

The hard "reset" generation setup sucks anyway, it burns Nintendo about 50% of the time. 50% of their hardware transitions since the SNES days have ended in failure or dissapointment (ie: Wii to Wii U, even DS to 3DS, N64 to GameCube). 

That's an insane business policy to reset to 0 like that every 5-6 years with a 50% chance you're going to lose a huge chunk of your audience. No other business would find that acceptable. 

Changing the way hardware models are offered and redefining it is important for Nintendo, now more than ever, because they don't have two systems to fall back on either. If for whatever reason the fickle audience doesn't like Switch 2 and you've 100% commited to the old hardware refresh set up ... you're 100% fucked because you have nothing to fall back on unless you want to be a smartphone app company. Too risky. Embracing a different model that's more like Apple is simply the better route to go. 

Some consumers will complain but they'll be a small minority. At some point you have to look out for the best interests of your company, not slavishly obeying the old "well I expect 6 full years of content" crowd, like some fat guy at an all you can eat buffet who still isn't happy after eating 30 pounds of food. That consumer is not going to be there to bail you out when things go tough they'll just be like "tough, I don't feel like buying a GameCube or Wii U or 3DS", they risk nothing, you take all the risk as the company, every time you change generations the traditional way, that needs to change. 

I would be interested to know why you are sure ?

Probably because those franchises are associated with handhelds so a revision that caters to the more handheld centric audience would be a good fit to release alongside those games.