1. The hybrid concept. While there was some overlap of 3DS getting some new first-party releases until early 2019, the Switch is combining Nintendo's portable and home libraries into one system. Now you only need to get one Nintendo system for their upcoming titles instead of two. The hybrid nature is also pretty seamless and easy to understand.
2. Games, games, games. This is probably even more important than the hybrid nature in and of itself. If you never had a Wii U, the first year of the Switch was staggering. Even if you did, you still had games not on the Wii U (Arms, Splatoon 2, Stardew Valley, Super Mario Odyssey, Skyrim, Xenoblade Chronicles 2, etc.)
3. Better marketing. Most Switch commercials are decent to impressive pieces of marketing. The Wii U ads were mostly cringy kids and their doofus parents.
4. COVID-19: Switch was the easiest to manufacture of game platforms during COVID-19, the library was already strong and growing by the time the pandemic hit. Switch also has some of the best if the not the best local multiplayer experiences of any of the current platforms. That helps appeal to families during a pandemic. We don't know where the Switch will end up in total units sold. But I have a feeling without COVID-19 it might've sold around PS4 & GB/GBC numbers. Maybe even more like Wii & PS1.
Lifetime Sales Predictions
Switch: 151 million (was 73, then 96, then 113 million, then 125 million, then 144 million)
PS5: 115 million (was 105 million) Xbox Series S/X: 57 million (was 60 million, then 67 million)
PS4: 120 mil (was 100 then 130 million, then 122 million) Xbox One: 51 mil (was 50 then 55 mil)
3DS: 75.5 mil (was 73, then 77 million)
"Let go your earthly tether, enter the void, empty and become wind." - Guru Laghima
