http://youtu.be/M8h8XYbvum4
In the video they say it takes 6 months to plan, photograph, and prepare a new golf course for 18 holes of stoke play here at WGT.
A Forbes article about WGT mentions it takes about 3 weeks to photograph 18 holes (about 300,000 photos), at a cost of several hundred thousand dollars.
This year we will get Pinehust #2 in USGA US Open condition, and a bit later an 18 hole collection of the par 3's on the Bandon Dunes Golf Resort complex of golf courses.
Though not confirmed, because of a recent renewal of their agreement with WGT it seems Pebble Beach has been moved up to be available as an 18 hole stroke play course from it's previous scheduled inclusion date in 2019.
In 2015 we get Chambers Bay. In 2017 we get Erin Hills. In 2018 we get Shinnecock Hills.