Watch this - http://youtu.be/M8h8XYbvum4
WGT has to reach a licensing agreement with each course it adds, and WGT already has a pretty full schedule of courses to add in the next 18 months or so.
As shown in the video the actual production of the course requires 6 months. 200,000 to 300,000 photographs of the course have to be made, and many of those have to be made from a helicopter. The photographs then have to be processed into the images we see when we play WGT, and coupled with the programming that defines the physical structure of the golf course.
Very near completion for 18 hole stroke play is this year's US Open venue Pinehurst #2.
Already photographed and in progress is an 18 hole stroke play course made up of select par 3's from the Bandon Dunes resort gold courses.
After Bandon Dunes we will get Chambers Bay (2015 US Open venue) and because of a newly renewed and expanded agreement with WGT we may also get Pebble Beach for 18 hole stroke play in 2015. PB was slated for addition in 2019 when PB will again be the USGA's US Open venue.