Regarding self-replication, this is an interesting field of exploration (I come from robotics where people have been fascinated with self-assembling robots for decades). However, there's a whole world of things out there to print other than 3D printer parts for your own printer. The MOD-t is designed for people who aren't necessarily interested in 3D printers per se, or even 3D printing per se, but are more interested in having the capability of making their own customizable stuff at home.