>There is nothing rare about rare earth minerals

Many heavy rare earth, i.e. the strategic stuff, is actually rare in terms of economic extractable sources we know of, mostly ionic clays found in China and parts of south east Asia I think also Brazil. It's the same reason PRC is the largest oil importer even though on paper PRC has the largest shale reserve in the world (more than the US), their deposits are just very deep in the desert, technically extractable but not remotely economically to the point where it doesn't even make strategically (not for lack of trying). This without even mentioning behind behind in extraction tech.

China has started in recent years to increase production of liquid fuels from coal (essentially what Germans did in WWII but much improved). That competes with oil when prices are above 80. With that it makes no sense for them to even try shale as those will be more expensive.