You know, from an engineering standpoint, I never understood why power meters didn't begin in the pedals. When I first heard someone ever mention a power meter, I assumed that was where it was implemented.
And the whole price thing -- its just like Apple products -- they just charge that much because they can. There's nothing too new about it and load cells have been around FOREVER. I'm seriously considering building my own set with the help of an EE I know.