The price of grain or oil doesn’t drop if the supply only increases marginally and that increase still doesn’t meet or exceed demand. That is especially true if grain and oil sellers decide that long term profits will be higher if they set a price based on the current market and hold or let spoil some of the product that doesn’t sell, while making fewer sales at a higher price point. People in here learned supply and demand in high school and just regurgitate that term as if it will cause some magic fix. There are literal studies and theories widely accepted in macroeconomic circles that argue capitalist society has moved beyond supply and demand based concepts for staple goods such as housing, food, etc.