It does have a chance of outselling those 3 combined. The PS Vita doesn't add that much to the total. If the Switch gets too far ahead of the 3DS and Wii U I can add the PS Vita.
I think it has a chance as well, I'm just saying that's something the detractors would resort to if it beats 3DS+Wii U but not 3DS+Wii U+Vita.
And of course no matter how well it does they will always be able to gloat about it not passing DS+Wii.
When the herd loses its way, the shepard must kill the bull that leads them astray.