I'm willing to bet that the other OPEC countries aren't in the same boat as Saudi Arabia. While they may be able to soak up billions in losses the others may not be. Historically, OPEC has lowered production when gas prices begin to slip to try and maintain the price high. So some of the other countries are barely(if they can even afford) able to afford the low price as is. Reduce production, now they have low prices and less barrels on the off chance the price will go back up.