Intrepidarts:
will it be back - can the system handle more courses without losing the ones we have ?
I suspect there was a time limit as part of the WGT/Oakmont agreement to have Oakmont here on WGT and Oakmont elected to not renew the agreement when it timed out.
I think there is limit to how many courses WGT can have, but WGT and the golf courses have to reach a legal agreement for a course to be added to WGT.
When Pebble Beach last renewed with WGT they let WGT photograph the entire course so it could be available to us for 18 holes of stroke play several years before Pebble Beach was scheduled to again host the U.S. Open (2019).
So it's a 2 edged sword - sometimes we gain (or courses renew the agreement), and with Oakmont we had had the first loss.