It is a very odd situation is why.
The Wii and DS were confident, explosively popular products (after a small misstep on the DS at the start) with new ideas that caught people's attention, and absolutely razor sharp marketing and positioning. And as a result were the two most profitable gaming platforms of all time and massively successful. The Wii in particular was a true zeitgeist product.
They were followed by two confusingly marketed, poorly positioned platforms. Too expensive, gimmicks most didn't really want, poorly designed, poorly named, you name it, they had the issues. Nintendo doubled down on 3DS and managed to recover to some respectability, but the Wii U was DOA and nothing ever really revived it.
Now the Switch is a massive return to form. Great name, new ideas that have resonated with the public, great design, razor sharp marketing, and clearly a positioning triumph. And is once again seemingly explosively popular, at least so far.
It's like Nintendo's recent (since the DS) run of scores for market positioning/design/success has been:
9/10
10/10
3/10
1/10
9/10
It's just hard to believe the same company has that record, it's such a bizarre record. As such, things making the Switch look more like the Wii than the Wii U are notable.