Some people are predicting Switch will outsell the PS2, so maybe this thread should be renamed "Will the Switch alone outsell the Xbox, Xbox 360, and Xbox One combined?"
Xbox - 24.65 Million
360 - 85.80
One - 50.04
Total - 160.49
PS2 - 157.68
So yeah, I personally think that's a HELL of a stretch, but based on some analysts I'm hearing and reading, it's entirely possible.
My Console Library:
PS5, Switch, XSX
PS4, PS3, PS2, PS1, WiiU, Wii, GCN, N64 SNES, XBO, 360
3DS, DS, GBA, Vita, PSP, Android