I saw an OXE in a marine supply store in Petersburg, Alaska recently (listed weight of around 350 Kg, I think, and no price tag showing). Haven't seen one on a boat yet. Somebody's got to take the always risky first step - especially in a small remote market. Either a buyer willing to chance a purchase without much access to parts and service, or a seller willing to invest in a parts and service chain without many buyers.
It would be difficult enough to try selling, say, Honda outboards in small market already dominated by Yamaha. It would be even harder to introduce a largely unknown and untested design of outboard. On the other hand, remote commercial use seems like a natural market for a long-lived, economical-to-run engine, and there are many experienced marine diesel mechanics around places like that who are used to fixin' stuff. There are also a surprising number of people in some of these smaller remote places with enough wealth that spending 50 or 60 thousand dollars on an experiment or a toy isn't that big a deal.
It looks like a beast of an engine. I'm guessing I'll see one on a boat before too long.