Because that’s just the price for the dies, still need packaging, integration and then retail distribution. Also raw BOM is like 1/5th of the retail price usually.
You can buy oil on the market and take delivery, yes. Figuring out the logistics (tanker trucks, rail cars, storage tanks etc) will also be your problem though.
Commodities markets aren’t like eBay, nobody is just going to FedEx you a barrel of oil.
Currently they sell here in Germany for 409€ each, that's 6.25€ for half of each of the 16Gbit chips on that kit.