friendlyfamine on 14 January 2018
Whoever said it won't outsell Mario Galaxy is insane, lol
Odyssey in 5 weeks: 4.32m
Galaxy in 5 weeks: 2.3m
Odyssey still hasn't gone through December sales yet according to VG. It's most likely already at 7 million right now and is an evergreen title that won't stop selling unless a sequel comes out or it gets overshadowed by any more Mario games. But I doubt that will happen.
