I don't like the "nostalgia" accusation because it can really apply to anything. Everyone grew up with something, so why would the GCN have more nostalgia associated with it that bolsters it than, say, the GBA or Xbox 360 etc?
It definitely was the worst-selling console but a lot of that was because of stupid image reasons since the PS1 brought in a lot of older gamers and Sony/MS doubled-down on appealing to them. I've seen the GCN's biggest games--Smash Melee, Metroid Prime, Wind Waker, RE4--on plenty of top game lists and I think those four are as good as any top four from the NES, N64, Wii, Wii U or Switch gens (SNES is untouchable of course).
At a certain point though these conversations kind of boil down to "this game is awesome," "no it wasn't" though, and I think we're starting to approach that.
You're kind of doing a relativization gymnastics routine here. Nostalgia can
technically apply to anything, sure—but the historical treatment of different consoles makes it pretty clear that some systems were always regarded as classics, while others simply weren't.
Take the NES and SNES, for example. Their games never went through this supposed "they aged poorly" phase. No matter how big the generational leap was—from 2D to 3D, from SD to HD—those libraries were consistently seen as timeless. The critical consensus never wavered. With the N64, the revisionism only started
recently, and mostly because people began applying modern criteria in a dishonest way: obsessing over framerate, polygon counts, and comparisons to today's standards. But during the PS2 and even PS3/Wii eras, N64 games were still widely regarded as major classics. This whole "N64 aged badly" narrative is very new.
Now, the GameCube is a completely different story. It was openly and undeniably considered a failure for
decades. Not just in sales, but in cultural impact. Even Nintendo's own fanbase used the GCN as the cautionary tale—the example of what happens if Nintendo doesn't evolve, which is exactly what people used to justify Iwata's Wii-era direction. This sudden wave of GameCube revisionism only started after Nintendo began re-releasing GCN titles on the Switch and as emulators for the system became more robust. It's not that the public always saw the GCN as an underrated gem—the narrative is being rewritten now because the games are accessible again, being polished up, and being introduced to a new audience.
So when you say we're reaching the "this game is awesome / no it isn't" stage, I don't think that's quite accurate. The point is that the historical consensus about the GameCube wasn't ambiguous. The perception only shifted recently, and not because people suddenly discovered hidden masterpieces—it shifted because the ecosystem changed and nostalgia finally had room to grow where it previously didn't exist.
Perhaps Iwata is smarter than we imagine and foresaw that it wasn't worth competing in the adult market spend tons of money so they adopting a second-console strategy. The challenge for Nintendo is that Sony will reinvest in games based on colorful characters because the lack of fantasy has made the Japaneses avoid the platform. I think Nintendo found itself this way, and this is how the company will always be; those who like it will have to like it this way and not wish it were different. I don't like it, so I don't buy it.
That interpretation doesn't hold up when you look at the actual history. Nintendo didn't adopt a "second-console identity" because Iwata foresaw anything—it did so because the GameCube had already failed in the very market you're talking about. Wii was a reaction, not a prophecy. And if Nintendo had truly "found itself" back then, the GCN wouldn't have been treated for decades as a commercial misstep, only now being retroactively glorified because of Switch re-releases and better emulation. Meanwhile, the NES, the SNES, Nintendo's handhelds—which they dominated so thoroughly that Sony eventually left the sector—and the Switch itself, which for many people is a primary system, all prove that Nintendo
can compete directly without relying on this supposed "niche" positioning. Saying otherwise is pure fanboy mythology.
The contradictions get even clearer when you look at Sony: their current shift toward more colorful, fantastical games shows these strategies are contextual, not fixed destinies. Claiming "Nintendo will always be this way" simply doesn't match the historical cycle of how the company has actually operated. If you don't like their current direction, that's fair—but turning it into some eternal truth ignores market reality and feeds into the same revisionism that's now rewriting the GameCube era.