Waiting until last to announce the NX was a good move because whoever announced their console last would be the one people's attention would be most focused on.
Literally, neither of these things are related.
This is just a delusion made up by desperate Nintendo fans, any economist would tell you that most consumers don't actually think like that.
Consumers have their own interests and things they look forward to. They won't be interested in a product just because "it's the latest announcement". They have expectations, standards.
As I'm sure you know, one large standard gamers have is specs. It drives hype for a console, the idea that you are getting a beast of a machine is appealing to the majority of consumers. So if the NX launches and is less powerful than the competition, do you really think people will get excited about this just because "Nintendo kept their announcement until last"? I'm not saying that's the only important thing a console needs, but it's an example of something consumers expect.
Like, name me one example of a product that did better than the competition BECAUSE it launched/got announced last. No, not just a product that HAPPENED to do better and was the last to be announced, but show me an example, and explain to me WHY that announcing last helped that product do better than the competition. It doesn't even have to be gaming related.
And I doubt Zelda's the only ace in their deck right now, the software drought is so obviously the calm before a storm that you can smell the water in the air and see the clouds billowing in the distance.
I don't doubt they have some bigger games up their sleeve, but let's not assume they will be god tier amazing, and let's definitely not assume having good games is enough to sell a system. Wii U actually has an excellent exclusive library if you go by objective game quality, from 2013 to 2015 at least.
I really, really feel like Sony and MS releasing both a slim AND a ~new~ shiny console might be shooting themselves in the foot.
If the casual market couldn't get that the Wii U wasn't just an expansion then how is PS4 pro or Xbox Scorpio or whatever gonna do?
No they aren't, because the difference was that Wii U was an actual new generation of console.
What Sony and Microsoft are doing are simply giving consumers more options for the same system. In the PS4's case, it's really clear and based off an established branding Sony has (every PlayStation console has had a slim model, and the PS1 and PS3 both had upgraded models as well).
People know that it's only a new Sony home console if it's a new number. If there's no new number (PS5, for example), they know it's not a new model. It's as easy as knowing the difference between iPhone models for the average consumer.
Nintendo names their systems something completely different almost every time anyway, so it makes it confusing as to whether something is an iteration or a new console altogether.
Heck they even have examples of contradicting themselves. Game Boy Colour was a genuine new system for them, but Game Boy Advance SP and Game Boy Micro were not? That's confusing.