Note that if we ran out of samarium and neodymium tomorrow, we'd still use SRMs instead of induction motors. SRMs without magnets are still extremely efficient, just larger than induction motors. Despite being larger they are still cheaper as the extra weight is steel instead of copper.
SRMs had a high barrier to entry and benefitted strongly from better characterization and new electronics (SiC). Now that they're hear there isn't much point in going back to induction motors, unless copper becomes drastically cheaper.
I will also point out that neodymium is the most widespread and second most common REE, and is in fact unusually less common in China. Mines in the US are closed because of the capital and labor costs, not availability. Neodymium is >10x more common than most REEs.
SRMs had a high barrier to entry and benefitted strongly from better characterization and new electronics (SiC). Now that they're hear there isn't much point in going back to induction motors, unless copper becomes drastically cheaper.
I will also point out that neodymium is the most widespread and second most common REE, and is in fact unusually less common in China. Mines in the US are closed because of the capital and labor costs, not availability. Neodymium is >10x more common than most REEs.