Honestly, the easiest way I see them achieving this is just not using a workforce and letting everyone starve and prepare for when the economy crashes into the literal core of the earth. They could easily have enough food ready as they see the crash coming or in the middle of it, they still would have buying power above others, especially for labor.

Edit: before we get too deep here, i understand their power would go with all that and it would be a lose-lose scenario, but i don't believe the wealthy and powerful would weigh that foresight over cutting labor costs and i see when the process starts they could stonewall any progress to feeding the poor.