That makes no sense whatsoever. We are not consuming rare earths; only moving them from one place to another.
Arguably, future generations would find it easier to mine them from former landfill sites, where they would be present in concentrated form, than from some distant mine in the middle of nowhere.
Will the NIMBYs of the future allow for rare earths processing in long defunct landfills that in the future are surrounded by residential development? These urban landfills even today really aren't far from civilization. In fact they have been enveloped by civilization in many cases.
I mean as it is you can't even recycle most things if they are the least bit soiled since it is not economically viable to implement a cleaning process. We are doing a whole lot of assumptions that our future members of our species will have solved a way to reliably get pure rare earths from a mixed up slop of everything in a landfill. Whatever they possibly figure out is going to probably be far more challenging than ore refining processes we use today.
It might be cheaper/easier to try and capture an asteroid than to refine a landfill.
Arguably, future generations would find it easier to mine them from former landfill sites, where they would be present in concentrated form, than from some distant mine in the middle of nowhere.