Let's break it into pieces.
I suggest you read again as he doesn't say it won't surpass the Wii U but says it's in the same basic power range much like Wii is to GC which kind of highlights the way you're looking at things which tbh is in a narrow minded way of trying to see thing.
Straight from the OP:
A lot of signs seem to point this way. Nintendo took a poor selling console in GameCube and repackaged it as the Wii (basically) before. Would you be angry if NX is basically about as powerful as a Wii U, but has the functionality of a portable while also being able to stream to the TV and act as a porta-console?
"As powerul as a WiiU" and what you say with "it's in the same basic power range" is like saying that it won't surpass WiiU.
Merging portable and console is a viable strategy to go for because one of Nintendo's main issues is spreading resources across two platforms, if you look at the output of Nintendo each year they've put out enough worth while games to beat out or match any publisher in quantity on top of quality the issue is that it's across two platforms so two separate libraries.
No one knows if merging both devices is a viable strategy because no one has ever done it before. It can work but it can also fail, there are no guarantees.
Also, I'm perfectly aware that how powerful Nintendo is as a publisher, but there's one caveat here with them supporting a single device: new IPs. If NX is a single hybrid console the case won't be IF Nintendo will make new IPs, but HOW MANY they will have to create. Why? Easy, unless you want them to launch twice as many Mario games (2xMario Karts, 2xMario 3D and 2D platformers, 2xSmash Bros, etc) they will have to create new IPs to avoid bloating the market with the same characters over and over again, damaging the value of those IP.
And before you say anything, of course I want Nintendo to make new games and IPs, and I know that Nintendo can create great new IPs like the recent Splatoon, but they've also made games like NintendoLand or WiiMusic thinking that those would be successes... They are not perfect.
The fortunate thing is that on the handheld side of things they've crushed the competition but on the console side of things they're out matched but two bigger companies, it doesn't help that portable games are now equivalent to developing a full on console game so what you see as an experiment is actually one of the only realistic ways Nintendo can end droughts on their platform and also enticed third parties on board more so then just building a me 2 console with more power that will get ignored regardless of power.
Sorry but, do you really believe that an NX with the same power as a WiiU will entice third parties? This is what is happening now with third parties:
- Western Devs/Publishers_ They stopped supporting handhelds a long time ago. Some still make a couple of small games for 3DS or PSVita, but the truth is that their mentality is either go big (expensive games with great graphics) or go small (mobile). There is no longer a middle term.
- Japanese Devs/Publishers_ The situation seems to be similar than in the West with one caveat: handhelds are more important than home consoles. Console gaming in Japan is almost niche (I'm exagerating to make my point), with most of the development of Japanese games targeting handhelds. The problem is that handhelds are also losing ground to mobile gaming and many big publishers like Square-Enix are releasing more games on mobile than on handhelds. And that's a trend that doesn't show signs of change. So you have big, international projects that go to home consoles because that's what sells in the west, small projects that go to mobile and Japan centric games that go to whatever platform the devs think will have more success.
- Indies_ The way most indie studios work seems to be "make the game for one platform and then, if it's cheap enough and there's a chance to success, port it to the other platforms". Form factor doesn't seem to be a problem and neither is power, as long as there enough of it.
Now look at Nintendo and what NX will be acording to the suposition made by the OP: Indie studios are already working on WiiU and 3DS so as long as the conditions don't change, they will still work on NX. Therefore, no change. Western devs won't touch NX because it will be underpowered compared to PS4/X1, and a joke compared to PS5/X?. Therefore, the situation will be the same or even worse as some won't even bother to have games at launch to test waters. And then we're left with Japan, which I think will treat NX like they treat 3DS. So again, the situation won't change much.
Of course, NX can be so cheap that it becomes a huge success, but look what happened to the Wii. Despite being the best selling console of the gen, it was also the one with worse third party support. So selling lots of consoles doesn't guarentee third party support either.
No, anyone who thinks NX will regain third party support, specially in the conditions stated by the OP, is in denial.
No they didn't say it's not the successor of the 3DS and Wii U they said it's won't just be a simple replacement meaning it won't be the same thing only with more power its never been denied it's a replacement Nintendo are only avoiding saying what NX is replacing because it would impact sales of the current platforms.
Given that we still don't know what NX is in terms of hardware other than what we have speculated it could be (home console, handheld, hybrid of both or two systems with shared functionality), the discussion about if it's a replacement, a successor or a complement (a third pillar of sorts) is rather pointless.
You're free to not be confident about it but the main factor standing in their way here if it is a hybrid console won't be X1 or PS4 it would be Vita as the portable market is Nintendo's anchor and even if half of 3DS owners bought the NX that's still 3 times more sales then the Wii U and with Vita as their main competitor the odds are really good as Sony won't drop PS4 to create a Hybrid console anytime soon in fact it seems they've left Vita to its fate. One platform would also make marketing and all much easier as it's only one platform to focus on and Nintendo would have to push it hard being their only platform like how they did early on to turn the 3DS around.
"even if half of 3DS owners bought the NX that's still 3 times more sales then the Wii U and with Vita as their main competitor"...
If NX only sells half the numbers of the 3DS it will be labeled as the worst mistake ever from Nintendo, including the Virtua Boy. There's no way Nintendo could get back from that, it would be the end.
And of course Sony won't do an hybrid console, they don't need to.