Idk how many times it needs to be stated that Switch and 3DS are two seperate systems and appear to be on different trajectories.
3DS after 11 months was at 4.27 million and Switch after 11 months is at ~5.15 million in the US.
In Feb/March 2012, 3DS did 260k & 220k while Switch looks to do ~300k in each.
That puts 3DS at ~4.75 million and Switch at ~5.75 million after 13 months.
The fact that Switch is tracking over 20% ahead of 3DS at nearly twice the price should be all you need to realize that Switch is most likely going to blow past 3DS in the US.
its going to beat 3ds but beating xbox is not a sure thing, especially with how nintendo consoles usually lose momentum much faster.