It seems to me that those bought the XPro3, or at least those who bought it and made videos about it usually claim that they know what they are doing and are glad that Fuji's not afraid of making things different, but these people don't seem to have to rely on this one camera for their money making projects, rather more fun for themselves.
So is it a success? I think there's a market for it and there are definitely people finding it interesting and that's the point right? To make stuff that people find interesting and want to pay for, and Fuji will undoubtedly find new ways into the niche market so this will be their thing until something else appears IMO. The only trend I see is there will be work cameras, ones we debate over having articulate vs flip screens, and there will be fun cameras, ones may not even have a screen.