Mining is not limited by human labor, we already use huge machines (and some robots) controlled by a few humans. The limitations are investment in huge machines and processing plants, and regulations on where/how you can mine/process.

You can't just have a robot start mining/processing rare earths, anywhere in the country. You need permits, and a lot of money. I guess that didn't stop AI companies ... but there isn't an "infinite" novelty/hype premium for rare-earths, like there is for LLMs.