I think that people are so negative against Nintendo that if there isn'ts some power behind it, it's going to be as dead as Wii U when it comes out. This thing is competing against not only Xbox One, ps4, ps4 pro, Xbox one Scorpio, Ipad, Samsung Galaxy Tablet, Old xbox360s and ps3s, PCs, Wii u, 3ds, Android TV, Cell phones, Razer Forge TV, etc...
I think the smartest thing to do for Nintendo is have scalability. Nintendo needs Switch to be a unified operating system platform, but it could have different levels of power. I think the best way for Nintendo to skip the power arms race, is to disrupt it.
Also, I would imagine Sony and Microsoft have paid corporate spies. They probably knew about Switch, and that's why PS4 PRO and Scorpio had to come out.