Nintendo's appeal has been mostly in the handheld market for the last 20 years with the exception of the Wii. The Wii was Nintendo's most exciting console outside of the NES, nothing else really came close. Even though the DS sold better overall, Wiis were largely bought for multiple people to play whereas DSs were usually only played by one person a piece.
Overall, Nintendo hasn't really had much in the way of an exciting home console outside of Wii and NES, the success of SNES was largely due to it being the status quo, it wasn't anything special like the NES. The N64 should have flopped, it was a terrible system that used cartridges, and PSX had Resident Evil 2, Gran Turismo, and Final Fantasy 7, it was much more exciting than either the N64 or SNES. The GameCube did flop because it was completely unappealing to anyone except children who were looking for a children's version of Playetation 2, because that's all it was, Playstation 2 was exciting because of Final Fantasy, Metal Gear Solid, GTA3, Vice City, and San Andreas. . The Wii was something very unique with new methods of control including motion, IR, and classic inputs, and usurped the throne from Playstation as being the most exciting platform, and as a result, stomped it. Wii U didn't excite anyone, there are no flagship titles on it outside of Mario Kart 8, it is missing a proper Mario game and a proper Zelda game is coming 4 years too late.