Gold is a store of wealth because it's a metal with very useful properties. If it were cheap everything made out of copper would be made out of gold instead, but there isn't enough gold to do all that, so it can never be cheap.
Copper is a better conductor than gold, and it's lighter. Gold doesn't corrode. So only if you're concerned about corrosion, you'd go for gold. In all other cases, you go for copper. Hence, you'd expect gold to be cheaper than copper if both are equally abundant and gold isn't used as store of value.