Yes. The cost is somewhat due to construction and somewhat due to limited demand. They need to be pretty thin around the shoulders (1-2mm thickness) and impose zero restriction on stroke movement but reasonably thick around the legs (5mm thickness).
Having said that, for sprints in certain locales at certain times of year the wetsuit is purely optional, because the time gained from the wetsuit in the water is about equal to the time lost removing it in transition. For all longer distances it would be slower to race without one, though.