I agree - though none of those examples are niche or well suited for 3D printing (except maybe the robot). It's not a question of whether the technology will continue to improve (it will) but how it will evolve and what it will be used for. Most manufacturing is complex and benefits from scale, not only economically but in terms of quality assurance. I wouldn't want to drive on a 3D printed tire (and I bet my insurance company wouldn't either). Furthermore, it seems the companies who design and manufacture goods would be hard-pressed to give that part of their business up and so long as they can produce goods for cheaper than you can make them on your own, 3D printed alternatives will be relegated to niche categories (i.e. luxury goods).

I do think that homes will have 3D printers in the near future, though I don't think it will be as a cost-saving measure or alternative to traditional consumption. Rather I think it will serve an educational/ entertainment purpose if its not being used in some professional/ prosumer way.