The only thing I can think of is that China in the short term but also long term want to maintain themselves as the lowest cost supplier of rare earth's. So even if there were competitors in the USA for example, companies would be paying a premium to acquire those rare earth's, thus impacting their bottom line.
In the short term this might not make sense because in theory given that China controls most rare earth output they could spike the price to whatever they wanted, however doing that could force an even further rush from the rest of the world to diversify away from China, and China isn't in any rush to give up any of their dominant market position!
All imo.
PM8 Price at posting:
21.5¢ Sentiment: Buy Disclosure: Held