It would be interesting to know how the "destination golf" resorts/clubs have been financed and how leveraged they are on an operating basis. My guess is many of them (Bandon, Streamsong, Barnbougle, Cabot Trails/Cliffs, Sand Valley, etc.) were able to acquire their sites at very reasonable prices. It is not like those sites were high value or high use real estate. Not having a big monthly mortgage payment can give these places some breathing room if/when there is a downturn in their revenue stream.
Many are "financed" by wealthy people who want to do something great, and know how to work the system to get tax breaks etc from localities eager to have a great project providing jobs and tourism $ in their backyard.
I do not believe any of them are really "leveraged" in terms of financing, because banks have no interest in lending money for golf development -- they saw the carnage from 2008 and they haven't gone back. [Honestly, it's the expensive renovations funded by local bankers which are more likely to result in a foreclosure event.] But many do take on outside investors, who might take a haircut when the economy eventually has a hiccup.
Development itself [all types] is a boom and bust business; when someone has a working formula, others try to copy it, and that just accelerates until the model fails and the situation changes, because there is no such thing as central planning. There is always a bubble, and it will pop eventually, and prices won't keep rising, and some places the prices will fall, and other places may fail entirely, depending on how they were financed. [Although if they are really good courses, someone else will come in and buy them for 40 cents on the dollar, and they might wind up being a bargain.]
The fact that prices are still rising means we have not hit the saturation point just yet. But the fact that golf courses take 3-5 years to develop means that some people will be left naked when the tide goes out.
There are also places, like Fall Line or Tara Iti or Ardfin, funded by guys with so much money that they don't really need to be successful. Is it a bad thing they spent some of their money on golf?
P.S. I don't know the % of international revenue for Bandon, but I know at Barnbougle it's never been as much as 10%, and I feel secure in saying Bandon is even less than that, because the domestic market here is so much bigger. You could also call Royal Melbourne a "bucket list destination" and their international business is a tiny % of the whole.