Yeah, it is a lot of money. But then people buy MOM-8's for $750, and probably have a couple hundred bucks per person in vests and tethers, a few thou in a life raft. Brion Toss has seized D-rings to shrouds for people in the past. By the time he charges rigger rates to do that work, the cost is similar. People doing a lot of offshore work probably won't flinch at $300 if they like the concept.
On the other hand, I can see why Johnson didn't commit to a production run of hundreds or thousands of molded stainless units when the max demand will be small in any case. There are lots of people who are convinced that the only proper attachment method is a jackline tape running along the deck within a couple feet of the toerail. I prefer being able to work at the mast on a 3-foot tether myself.
Tuesday we're off for a week charter out of Tortola with our son, future daugh-in-law and future co-inlaws. Woo-hoo! Can't wait!