Well that's a somewhat discriminatory way to look at things. A counter-example to some of the stuff you said about Japanese robotics is the work SCHAFT has done[0][1]. SCHAFT was a spin out company of the Tokyo JSK lab that came up with some revolutionary new electrical actuators. They dominated the first DARPA robotics challenge because of this and got bought up by google. There are european robots that explore new algorithms and technologies[2][3].
But if you really want to talk about robots that make cars, Japan leads the world at making them. And this is what matters. Sure, America might have the best biped robot in the world right now, but Japan has the tooling to mass produce it on a large scale.
[0]: https://www.youtube.com/watch?v=C3JCd7ooILo [1]: https://www.youtube.com/watch?v=fwoFjzLZ5rQ [2]: http://roboy.org/ [3]: http://www.rsl.ethz.ch/robots-media/anymal.html