After playing the first round at SE during the 2006 KP I opined to a couple of participants that I did not understand the development's business plan and that I doubted it would succeed. Though I am a big fan of Mr. Doak and like SE, I thought the site was too harsh and the course too difficult for the intended market.
I have no idea how much it costs to maintain, but my guess is that it would need a fairly good volume of rounds and a fairly low capital structure to succeed. With the ample number of alternatives on more benign ground for affluent, older golfers, I don't know that a private model works. It was already too hot in late May, so is the season six or seven months long? Is the course good and unique enough to attract a national membership?