First off, there arent percentage bars on Amazon rankings, so there could be a 50% difference between say #1 and #2 and you'd never know. 2nd, PS4 went out of stock quickly on Amazon during BF anyway. PS4, Switch, and XB1 were all in stock during Xmas week.
we'll see people say amazon is reliable we have no idea how true that is regarding switch. it seems like nintendo products do amazing there, we'll see.