Actually, I think that it's a matter of memory distortion. I mean, how many units launch games sold back in the day on some successful consoles? PS2, 360, DS itself.
And more importantly, did they sell during a longer-than-usual span of time, or just the first weeks after the release? The pattern of sales of launch games is usually different than games released on a mature console, since they follow more precisely the sales pattern of the console itself.
I heard about The Mercenaries 3D; I don't know exactly how many copies sold in the US, but I saw it in the UK charts, and in the Germany as well; in Japan it sold roughly 100k copies, which is not too bad considering the genre and its nature. But can we judge its sales now? Or maybe we have to wait some months? 3DS is not selling so well in the West and obviously the sales of the software are highly influenced by this situation; but when (if) the console start to sell better (from october for example), also the software already released might be sell something, since there are not so many games so far, and the userbase will surely get bigger. Games like The Mercenaries 3D (crappy but with a famous name), Zelda and Street Fighter will be the choices to purchase with the console for the average consumer so they should sell in a longer span of time.
And I think the point is here: Tekken Tag Tournament on PS2 sold what it sold (3mln? 4mln?) in 3-4 weeks or 2 months, or in 2 years, untile Tekken 4 came out? And Luigi's Mansion? All of these games, those which sold well, did in line with console sales, becoming inevitable choices for those gamers who purchased the console in the first year(s) after the launch.
So we should wait at least after the holiday season, when Nintendo will try everything to re-launch the 3DS; if until now Super Street Fighter IV: 3D Edition has sold 400k copies, in early-2012 may see 600-700k, and The Mercenaries 3D 300-400k, which are not bad results at all and could make the userbase grew. Obviously, the console must sell well at the end of the year.