"China is estimated to hold an about 84% share of the global market in neodymium magnets and an over 90% interest in samarium cobalt magnets. Japan, meanwhile, has about 15% of the neodymium magnet market and a less-than-10% share of that for samarium cobalt. If China bans the export of such technologies, it would be difficult for the United States and Europe, which do not traditionally manufacture rare earth magnets…
China has been dumping rare earth metals and magnets at ridiculously low prices for decades (and polluting their country). This had the effect of making mining and refining these metals unprofitable in the west (why pay the huge price of pollution when the Chinese will contaminate their ground water below costs?).
This doesn't mean the west can't scale up prospection and innovation to have cleaner ways to make these magnets. There's little to no tech gap the Chinese have over the west.