The story of
DMM is a long one, but in short it was a good idea that was poorly executed.
The idea behind
DMM airport is to have a single efficient airport serving both Jubail and Dammam areas, replacing Dhahran and Jubail airports.
This airport covers a large and important catchment area: Jubail is Saudi Arabia's main indutrial city and Dammam is the main oil and gas hub and is one of the major business areas. They have a combined population of over 2 million, and the then main airport (
DHA) was busy (it was busier than Riyadh). So the projected traffic was a lot higher than it transpired.
Construction started in 1984, however it suffered many problems. The airforce meddled (they wanted the airport), and as the project progressed the cash flow got tighter, to the point that near the end the project was moving in drips and drabs. Although very late, it was rushed into service, and it was disasterous. The airport had to shut down soon after opening because of technical problems (power failures if I remember correctly). Also, only the north access road was finished at the time, and that made for very long journey times for people from Dhahran or Khobar.
The poor reliability and long distance pushed many locals to abandon using the airport and go via Bahrain, which is linked via a causeway, and Dammam's loss became Muharraq's gain. Very quickly, foreign airlines figured out that they could consolidate their operations in Bahrain, and just offer a bus/limousine shuttle to Dammam from there, so airlines left in droves.
Things have improved a little now. Traffic has started to pick up again, but it's too late.
BAH has taken it's market. It's a shame really, because it's a nice airport.