Sorry to dissappoint you, but the droughts will happen for the Switch as well. The Wii U didn't face droughts because of the 3DS, that is nonsense. Nintendo always supported their handhelds, even before the SNES was released, and they didn't have as much droughts on their main consoles. And it's not like the 3DS was extra-supported by Nintendo or anything. If you count the games and look how many years the thing was out, it got less support than the original DS and GB. And it faces a similar drought from 1st party for some time now.
Also, you don't seem to realize how Nintendo operates and how game developing works. There is a reason Nintendo tries to make each portable similar to the power of an earlier home console: They can port games, game engines and assets, and have them run well with minimal alterations and work required, compared to creating a game from scratch. See that Super Mario 3D Land? Its engine is from Super Mario Sunshine/Galaxy with some changes to better fit the 3DS. Zelda's is Twilights Princess. Fire Emblem's is a directly from the Wii u. Etc etc. The only thing that changes is the resolution output, lower resolution textures, 3D support, plus some 3DS specific changes like usage of its special shaders. All it takes then is a recompile for the ARM architecture. That's about it.
So, Nintendo didn't have to pay so much money to develop games for the 3DS. Nor they needed really large teams. Their major focus was on the Wii U, but they have been stuck in the past. Nintendo doesn't like to invest money to please its customers. They like to provide 0 and ask for a ton of money for it. When a company is used to just port SNES games to a handheld and get rich, they think the good times will last for ever so there is no need to invest in better development studios, like other companies like Sony are doing. So the Wii U dev teams really couldn't compete much, because HD AAA development requires bigger and better organized studios, AKA investments.
Nintendo pays its greediness, that is why they are eventually going out of business.