HintHRO on 28 September 2018
It is under 1m for the same reason upcoming 3DS games will sell under 1m (Captain Toad, Luigi's Mansion, Kirby Epic Yarn etc), 3DS is dead. Nintendo wants to believe it's not because they don't want to make a 3DS successor now with Switch resembling a console and handheld hybrid. Also, Samus Returns is the second remake of Metroid: Return of Samus. You can't expect gamers to buy every remake like it's a totally new game.
So no, I don't think this is necessarily a bad sign for the Metroid series. We'll have to wait for Metroid Prime 4 numbers. MP4 is a brand new game on a new console with a healthy consumer base, so I expect it to do atleast 3m.
