Comeback..? They did that with the Switch as a whole, though, which was before any of this.

I also believe that KYM trends are not a very accurate indicator of global trends most of the time, being a small site and all that.

I think is more because the darned crown is a source of infinite waifus. If that crown didn't turned Toadette in Peach (Even if gameplay wise it was identical), this wouldn't be the case.
I guess the Mario ones are just that popular compared to others because those are characters that actually have access to it.