It's selling absolutely horribly. Say it manages a million. That's optimistic at this point.

For a Nintendo-developed game, that's simply horrible. The only Nintendo games to sell that little on the DS were Metroid Prime: Hunters, Golden Sun 3, the Star Fox game, some Spin-off Kirbies, and the Intelligent Systems games. Those games were the ones that are either misses or incredibly niche, and some might even beat a million with missing data. If you compare it to the Wii Nintendo games, it looks even worse.

It did by far better than Tekken. Same platform, tekken started a little earlier and has the bigger name. I wouldn't compare KI with DS-games yet, the DS has a much bigger install-base.

I looked up some other games to compare:

Kid Icarus has sold 360K in two weeks, with a second-week-drop of 51%.
Sonic Generations: 122K, 64%-drop (without Japan)
RE Revelations: 280K, -71% (without NA, USA adds another 100K and a 83%-drop, makes 380K if counted together global)
Zelda: 551K, -6,4% (it started in NA in the second week, third-week-drop is 63%)

Comparison is hard, because many games don't start at the same time in all regions. But KI holds well against even big names like Resident Evil. And the slow drop let hope for good legs.

The DS didn't have a far larger user-base when it started out, though. Quite a few on Nintendo's DS games launched before it reached the 3DS numbers.

Performing better than the second Tekken game to be on a Nintendo platform isn't that impressive either. Especially considering that the game is quite sub-par.

I obviously can't be certain of this, but considering that KI seems to have relatively high production costs (for a Nintendo game, at least), it's entirely possible that no Nintendo developed game has ever had higher production costs and sold less than Kid Icarus is going to. Its only chance of that not being the case is managing to outsell Metroid: Other M, which currently sits at 1.07 million.

Yes that is obvious. The Kid Ciarus sales are very good for now and such a niche game. Lets see the legs.

It's bound to sell 1 or 2 million over the next five years. Especially when it inevitably becomes "Player's Choice" and sells for $20.

That's not really a counter-argument. Its sales might be good for a niche game, but there's really no reason it should be limited to being a niche game. Outside of their strategy games/Intelligent Systems games, Nintendo games are virtually never niche.

Week three: great hold in the US, but bigger drop in Europe. Let's see how it sold in Japan.