A lot of the rare-earths are produced as a by-product of other mining activities. Also, as soon as supply is seriously in constraint, recycling technology for EOL products would be developed, and as the price of sourcing from mines increased, recycling rates would tend towards 100%. Ultimately, the mining product is not being destroyed in the production of something like a battery, so it is fundamentally different, and fundamentally more sustainable than burning a fossil fuel.