So the DS had an extremely slow start. The 3DS shouldn't have that excuse though, it's the successor to the second best selling platform in game history, the formula and brand momenteum should be there for it.
Much like the Playstation 1 to PS2 -- the PS1 had a sloooow start, but it had to build its brand those first couple of years. The PS2 rocketed out of the gate because it didn't have to.
The 3DS already has had a monstrous price cut, it was Mario 3D Land, it has Mario Kart 7, Kid Icarus Uprising, it has Resident Evil (x2), MGS, Tales, it has Mario Tennis, Zelda: OoT, available in many different colors, etc. Sales should not be this sluggish. Honestly from a game library POV, the 3DS is considerably stronger IMO than the DS was at this point.
Are you kidding me? The DS sold over 25 million units WW in 2009, "a few years ago." No other console in the history of the industry has sold that well, and you want the DS's successor to be matching that pace in its first full year? Get out of here. Have you ever seen a sales chart, ever? Let me give you a hint, they look like the curve of a bell. They start low, grow to a peak, and then fall back down until the console is discontinued. Every console ever released obeys this curve. They don't sell in a straight line, the same amount every year, like you seem to want the 3DS to.
The PS2 and the GBA had pretty strong first and second years, which the 3DS has basically matched. They are effectively the only consoles ever to manage this, excepting maybe the Wii. The PS3 and 360 didn't get this mystical first year boost you speak of from their established brands. 3DS did start stronger than the DS, which sold a measley 10M in 2005, while 3DS is well on its way to over 15M this year.