You hit the nail on the head here. The real issue with abundant rare earths is that over 95% of the global shipment of rare earths has historically been controlled by China.
Because of this, there's significant exposure to their export policies and hence high price volatility for these materials. For instance, in 2011, Neodymium saw a significant surge in price just because the government decided to limit export quotas.
but also at the same time, the prices of these metals are very low, thus suppressing interest in developing new mines. China is playing a fine balancing game here, because if they were to highly restrict access, then prices would justify heavy investment.
They control it yet ironically cant do anything with that control or else it will sow the seeds of destruction of that control.
Because of this, there's significant exposure to their export policies and hence high price volatility for these materials. For instance, in 2011, Neodymium saw a significant surge in price just because the government decided to limit export quotas.