And just to remind people. "Rare Earth" materials aren't actually rare. They're common. However, they are distributed in very very low concentrations, so you have to go throw mountains worth of material to extract measurable amounts of Rare Earth materials. This is typically energy intensive and ecologically destructive, which in most of the work equals "expensive" which is why the nations of the world have been happy to shut down their own Rare Earth extractions facilities any paying China to destroy its ecology instead.
China is free to set up its restrictions on exports. Other nations are free to restart their own extraction operations (with the costs that come with it).