According to NPD analyst Mat Piscatella on His Tweeter. Many Switch owner in US has PS4 or Xbox One on their possession, and Switch is not a substitution for home consoles, except it can coexist with PS4 and Xbox One and compliment each other. And many PS4 gamers and Xbox gamers buy Switch as their supplement instead substitution. The same trending also going to happen when PS5 and Xbox launched next year, Switch sales will still be big.
According to our PlayerPulse surveys, over 40% of Switch owners in the US also own a PS4 and/or an Xbox One. Switch isn't a substitute to PS or Xbox, it's supplemental. I don't see next gen HW launches having a meaningful direct cannibalistic impact on Switch sales in '20. Shrug— Mat Piscatella (@MatPiscatella) January 2, 2020