I dont think its because everyone has a PS4 or Xbox one thus why Switch is selling.

Switch is innovative enough that if launched first beside the failed WiiU would be outselling everything like the Wii did maybe even better. It hasnt had a full year on the market and has managed to haul in a good library. Lets be honest here, gamers who want to play shooters buy PS4 and Xbox one, want something else? then you buy a Switch. I think more people is finally wanting something else.