This thread has a really good subject and some truly excellent points for people to consider, especially if those people are considering joining and national/destination course.
John Kavanaugh makes a great point with his statement that "yes" the private national club business model will work if the membership is benevolent.
Also, Justin S's analysis is really good and highlights things that I think are valuable to consider/discover.
I am looking for a national/destination to join and have been looking for over a year. During this year, I've consider/discovered many of the things he touches on.
First off, if you are looking to make it work on a cost per round basis...I don't think you will ever join a club. You can alway find cheaper golf.
This leads to the second point, which builds on John's point. And that is this destination courses has to hold some special value to its members that is difficult to put a price on. Most likely that centers on the experience of playing golf on the course and/or being at the club brings out some sort of feeling that is not able to be replicated anywhere else. Find a group of people who feel this way about a certain course, and you will most likely have that "benevolent membership" that John talks about.
A few of these courses that I've seen people talk about on this site that appear to generate that feeling are, Ballyneal, Sand Hills, and Kingsley. The members I've met from these courses flat out love them. Nothing can replace them in their eyes. Frequent comments like "it is my favorite place on the face of the earth" or "there is no other place I'd rather be" are made on the courses. Other courses I've heard discussed like this from people who are not members of this site are, The Golf Club, Augusta National, and Cypress Point.
Perhaps the lesson to be gleaned from this is that if you don't have that special feeling for the club/course, you shouldn't join. There are a couple of clubs that I've stumbled across that I'd join instantly without doing any calculations at all on the finances. Maybe that is the deal, you want to be at this club so much that it doesn't matter the costs. As the "feeling" the club/course generates is, essentially, priceless to the members.
Frankly (as Justin touches on), I've had this feeling at some resort courses as well. So, those could indeed be a de facto national club for some people. And again, cost might not matter if the feeling is just so special.