Well, the date on it for "realization" was 2013, so . . . I suspect it was never a serious idea, but just an attempt at gaining some free publicity. At $500m, the golf course would be a pretty big loss leader for the rest of the project . . . maybe they figured they could sell 50 lots at $10m each?
You would think that if Troon Golf actually got paid anything to have a look at this, they should have pointed out that you can't have a golf course routing with two sets of holes playing east-west and one string of holes playing west-east. It's funny how often one sees stuff like that when land planners sketch out golf course routings.