The longer trend develops with the server life. Being on a newer server, you are probably at the stage where everyone is scrambling to get enough gold to pay for research. This creates a large glut on the market and forces prices down. Later in the server life, food, lumber and iron are needed in large quantities and gold becomes plentiful, so prices start to climb sharply.

I play on server 6 and food is currently at 8 and iron and lumber are around 18. I also play server 73 and nothing has yet reached 1 gold. It will happen in time, as it does on every server.