A lot of people conflate "knowledge" and "intelligence." Not the guy you replied to, they seem like a troll; but still, a lot of people.
Our ancestors had intelligence in spades. They figured out an insane amount of stuff just to survive; and it's not too far back in the grand scheme of things that they had to remember it all because they had no way to record it. The first caveman to make a handaxe had absolutely no idea what he was doing, but they figured it out. Wheels, bows, fire, the entire concept of agriculture... They figured out how all of that worked from scratch, with no reference material.
Modern humanity builds on that with knowledge. We've figured out how to record everything our ancestors discovered, and all of our new discoveries as well. We've put men on the moon, figured out how to make electricity from things like waterfalls and glowing rocks, and almost everyone has a tiny computer in their pocket.
None of that means that we're more intelligent now, though. All of that knowledge is iterative, so we've just been applying that same intelligence at a continually higher level throughout history.
I never really thought about their succession of consoles, but to me, seeing them listed like that feels surprisingly additive.
Like, the N64 had analog sticks, and the Gameboy was portable... And people liked both of those, so they released the GameCube, which had analog sticks and a handle, so you could take it to your friend's house. They followed up with the DS' touchscreen and the Wii's motion controls, and when people liked those too, they bundled all of that into the Switch: it has analog sticks, a touchscreen, and motion controls; it's a handheld and a very portable plug-in console.
But, as they've done that, they've always pushed the limits of what they could do. As it stands, there's not much that can be added to the Switch, so they're releasing an improved version - like they did with the Gameboys Color, Advance, and SP. Essentially, the limiting factor isn't Nintendo's ability to innovate, but rather the technology available to them.
Give it a few years for other aspects of technology to advance, and I'm sure they'll start pushing the envelope again. They'll probably wait until they can pack an entire console into a VR headset without a bulky battery pack, then release it with something wacky like a charging dock with a built-in projector, or something crazy like that.