Why not put a few tens or hundreds of billions (a tiny fraction compared to TARP or how much the US spends on the military) in to research in to these technolog

Why not put a few tens or hundreds of billions (a tiny fraction compared to TARP or how much the US spends on the military) in to research in to these technologies to make them less dependent on rare earths? How do you know how much something like that would cost to develop?