I see it as similar to the Sand Hills of Nebraska.
It's great land for golf, but between the harsh winters / restricted season, and the difficulty of getting there, it's a difficult place for anyone to make money in golf development. Indeed, to date, no one in the Sand Hills has made any money in golf development.
I'm more skeptical than most because of the little I know about the Australian golf market from my experience at Barnbougle Dunes. Barnbougle is extremely successful by most people's standards, but they only play between 20,000 and 25,000 rounds per course there, and they believe the customers are very price-sensitive ... it's only a bit over US $100 to play two of the top courses in the world, because Aussies won't pay more. That tells you that the same customers are influenced by the cost of getting there, and Barnbougle is cheaper to get to than King Island, because the government subsidizes the air connection to Tasmania in some form.
Also, the Australian market is not a bottomless well of golfers, as in America. Most of the people who would go to King Island are already going to Barnbougle, as often as they are inclined to go. As for overseas visitors, they are a tiny fraction of the business ... perhaps 1,000 rounds per year. They're the gravy, but there's got to be some meat and potatoes underneath, and those would be regular Australian customers.
There may be more courses, just as in the Sand Hills, because there are more people who dream of building a great links course. Really, the best chance of making money is for an existing project to build a second 18 - because they only have to pay for the additional course, and not much additional infrastructure. If those guys aren't building more courses themselves, then it's probably a bad move for anyone else.