It's a trend I've noticed a lot with Nintendo's new concepts on Switch, whenever it doesn't do Mario Odyssey, Breath of the Wild, Smash Ultimate, or hell, Wii Sports numbers, it automatically is deemed a failure, even before official numbers and expectations come out. 1-2 Switch? Failure (sold 2.69 million), ARMS? Failure (Sold 2 million), Nintendo Labo? Failure (Sold 1.4 million in its first few months, and has seen sales boosts during the holiday season, so it's probably at 2 million already).
The only exceptions to this rule are Snipperclips, which was eShop only in its original run, and Sushi Striker, a game that actually failed. 2 million is not a failure, at all. You may not like these games, but they have an audience, and are some of the Switch's best selling titles. Do people honestly think Nintendo expects everything to catch on like Splatoon or have the same audience as it? Or is it because these IP are reminiscent of the filthy Wii era, and thus, need to hold them to the impossible Wii Sports standard to justify their argument? Also if ARMS and Labo were such failures, why does Nintendo keep promoting them regularly?
I actually have not come across anyone calling these games a failure before. Some people in this thread have decided to take it on themselves to justify the point, but I am not sure they know what they are talking about. The games have flaws, true, or they may not like them, but that has no bearing on whether or not they are sales failures.
If anything, considering how these are fairly low tier games and still sold millions make them successes.