In fact, experiments have shown the opposite, people aren't entirely self-interested. Game theory has it's applications but they are limited. I can't say I ever ran across one that wasn't just something shoehorned into a situation. One of those was a game theory model trying to model systemic risk in the financial system, nice exercise but not very convincing. It most common in commodities for producers to do the opposite one might think. If prices are down, they will cull the herd and sell it off either for slaughter or alive. This is because their expectations are for prices to stay low, not just continue the trend necessarily.

The scenario here is a bit different. Whales have their profit and want to preserve it. Each downtick gives them angst and the future uncertain. Mkae of that what you will.