That was the question I had when reading this piece in Technology Review. The bottom line is that it's very hard for a robot to assemble an Ikea chair--inserting a dowel into a hole is right at the edge of perception. Robotics is getting there, but it's a pain. The logical answer is to redesign the world so robots can handle things. Unfortunately, that limits the available market for robots.
I assume we'll reach a point where new processes are designed for robots. (Maybe we've already done that with the chip industry? :-)