It is pretty clear that Switch conquered the US by now. PS4 doesn't even get close anymore. Though that could still change with a pricecut from Sony - although Nintendo can do the exact same, and probably will sometime this year. I mean, a console without a pricecut during it's first 3 years would be something radically new.
Conquered the US? Quite an odd choice of words when comparing monthly sales of a 2 year old console to a 5 year console that is still $299. Let me know when the Switch has passed the PS4's LTD, then we can talk about conquered.