The USGS produces annual reports for each mineral the US uses.[1] This is a lot of material, but it's all online. The rare earths report shows prices declining since 2014.[2] The rare earths aren't really that rare, just found at low concentrations.

Helium, though...

On the scale of a century, though, the reserves don't look that good. Some metals used in bulk, like copper and zinc, don't look so great. Remember that really high volume mining is less than a century old.

[1] https://www.usgs.gov/centers/nmic/commodity-statistics-and-i...

[2] https://prd-wret.s3-us-west-2.amazonaws.com/assets/palladium...