China should just conserve rare earths for its own use over next few centuries, rather than exporting them now.Josh, I think you need to read and follow some other threads which have already discussed the rare earth situation and Huawei's plans to survive in depth. You're basically bringing up those already discussed topics for discussion again here.
Regarding rare earths: https://www.sinodefenceforum.com/can-the-us-derail-2025.t8530/page-2
It's not a coordination problem; China's government is fast-acting for sure. They hold a meeting in ZhongnNanHai with CCP officials, and it's done. It's that this is a little too big a weapon to use. It's kinda like a nuke; to ban rare earths would cause incredible global disruption and turn everyone against China just as China got the moral high-ground over the US over the Huawei incident. This might still be resorted to if China were really crunched by the trade war/tech ban, to crunch the US similarly but when China is ready and it's got a fine plan ahead, it doesn't have to resort to this. No country would ever use a nuclear weapon against someone who they can defeat by conventional forces and that's why China's leaving the rare earth ban at home.
Also, since China's talking about it, it looks a little more like a head-fake rather than a real move as a real move should be kept silent until the last moment of announcement to inflict as much damage as possible. Here, it can cause some fear and panic in the US; they might start pitching their resources hurriedly into rare earth production, which won't really materialize for about 2 years, then they realize they've wasted their investment for nothing as China keeps underselling them and they have to close shop again or continue to government-subsidize operations that aren't really needed.
It's certainly not about war. China's not Afghanistan; you can't beat down nuclear China for its rare earths like you can beat down Afghanistan to rob its oil. Plus, after a Chinese ban, the US wouldn't be 100% cut off; they would just experience ugly shortages and have to invest huge amounts of money to go around looking for little bits of product. It would badly hamper them but it wouldn't grind the US industries to an absolute halt. The war option like how the US oil embargo pushed Japan to attack is not a usable tactic in a world of MAD.