Who did it: Nintendo
The 3DS is doing fine now. In fact, it's probably the only thing from the big N not currently hemorrhaging money from the company.
But when the portable system was first released, it was met with skepticism and low sales. The company had to do a sizeable price drop early on its cycle just to get most people interested in it. So what was the big problem? No Mario games at launch, that's what!
While there were a few good titles on day one (you'll never hear us complain about Street Fighter IV, never), the system could have sold like gangbusters if they just relased Super Mario 3D Land on day one. It was a game that truly showcased the potential of the handheld, and if it had been out from the very beginning, Nintendo could have kept any price they wanted. People still would have bought it. That's what happens when you're not patient. A great launch title is key.