I'd say the Sharp pricing is a combination of new technology - its RGB LED backlighting is more sophisticated than simpler rivals, allowing for a far wider range of colours and contrasts - build costs (the Sharp is wafer-thin) and a style premium.
Sharp owns a chunk of both Loewe and Pioneer - it seems to have worked with the former on luxury styling and the latter on technology; the sound system in the set is Pioneer-designed, for example.