The 3DS is bombing. Sales numbers are way lower than projected and Nintendo has already done a massive price cut in the hopes of increasing holiday sales and hype. Executives are taking pay cuts and apologizing to investors. The rumors are circulating that Nintendo is considering a hardware redesign already. They have rewarded early adopters with free games, but that doesn't fix the main problem, that people aren't buying their system.
I can't speak for everyone, but I can tell you why I don't own a 3DS. In a nutshell, I've been spoiled by the price of mobile games. I play games on my ipod touch almost every day and the most I paid for one was around the $8 mark but even that is the exception. 95% of my games were in the 1 to 2 dollar range. I get hours upon hours of play out of the games I purchase and for $1 it's a steal.
When I'm getting so much playtime for a few bucks on my mobile device how can I justify paying $30+ for each 3DS game? Realistically, I can't. It's not the full-fledged experience that I pay for on the PC or Xbox 360. The 3DS is inherently a mobile gaming platform. Despite the 3D hardware, with the prevalence of smartphones we have new standards upon which we judge mobile gaming. Unfortunately for the 3DS it's still playing by the old rules. It may be cool new hardware with a big name behind it, but I don't think fortune is in it's favor.