Even if you can’t transport metal there will always be an investor who can. It is the job of investors to keep markets efficient, not regular people.
Investors support the price floor, not customers. If prices fall too much below intrinsic value there should always be an investor in the market who will be willing to pay buy it at a higher price.
Think about currencies, or when you buy gas to fill up your car: regular people only make up a small portion of the market and it is the investors who act on a much larger scale who keep prices stable.