Orbx has stated in the past that the airports they make are snapshots in time.
They do not intent to keep them updated until some developer, being independent or Orbx's feels like it could use the update like they did with Brisbane and Stockholm.
Sometimes another developer makes a new version of an airport like Canberra for instance.
When Orbx made the airport, there was a large construction site. Now, there is a new version, not by Orbx, where the site is finished.