This is the reason they are doing what they are doing. They have made fundamental changes in their outlook on oil. They used to think that oil would be in demand for the forseeable future. But now they recognize things have changed. First the US oil boom, which is producing as much as they are, and second, we are starting to get viable alternatives to gasoline with electric vehicles. Oil producing nations can't price oil as much as they want any more, in fact they have to price it low enough that these alternatives are adopted more slowly.
The second change is that they know they need to get away from oil revenue, and 95% of their trade comes from it. They have begun a plan to increase non-oil inductry to get ready for the time they would be selling oil.