You speak of the normal cycle that would bring supply and demand back in check. But as with other things such as the labor market, do the cycles function in a global economy?
Sure. Commodities have always been part of the global economy*. There is a single price for commodities, subject to transportation costs and the quality grade of the commodity in question.
* It's labor and land that have been uniquely local, until the invention of the intermodal shipping container, which internationalized manufacturing by making it much cheaper to transport something from across the globe from a low-labor and -land cost country, than make it locally in a high-labor and land-cost country. Companies used to make products for foreign markets in those markets to save on transportation costs. With the invention of the modern shipping container, it is now cheaper for them to assemble those products in foreign low-labor cost markets and ship them back to their high-labor cost home markets.
That is why manufacturing jobs have been going abroad for decades. Even China is seeing this effect, as Chinese plant owners move their plants to Indonesia, Vietnam and Cambodia to capitalize on lower labor and land costs, even as Chinese land costs have skyrocketed, and Chinese incomes have gone up 10x or more over the course of 20 years, which is how annual Chinese car sales went up from 1m in 1992 to 20m in 2015.