The way I see it there is a little bit of a Nintendo fan in almost all gamers. When Nintendo comes out with hardware that's appealing as a first or second console and makes amazing first party games they will have success. The Switch is doing great because I think a PS4 first gamer sees the Switch as something complimentary due to the portability and have no problem picking up the hardware and thanks to great games like BOTW, Mario Odyssey and Smash games have been selling really well on the system. The Wiiu seemed like a burden to people as a second system because it was just weird. Games are also selling well because I think Switch owners feel like the freedom to play portability or in docked mode allows them to play their games in more situations and thus increases the value of the game to them. Its almost like getting two copies of the game. One for a console and one for a handheld.