Amazon uses tools for real time tracking to match prices it's finds at other retailers and or online stores. In the USA:
Do you really think the PS4 and Xbox One versions are both going to see low demand? If anything the PS4 will outsell both versions.
Supply and demand is most definitely a thing but trying to draw conclusions based on a sale price of a product that hasn't launched yet thats shared with a digital marketplace also along with an online retailer that literally has hundreds of partners that they work with which can affect the price at any time isn't going to give you conclusive data in any capacity.