That's a typical white boy copium, in reality:But as with the rare earths, China dominates here mainly because of its cost advantage. If supplies from China were cut off, gallium production in other countries would quickly pay off again.
1) Building mines takes time and it would have to be fully subsidized because it is not economically feasible. Moreover, every single product made from non-Chinese gallium\germanium would have to be subsidized to be cost-competitive against products made from Chinese rare earths, otherwise all that effort is going to be useless.
2) China dominates rare earths refining even more than mining - both in terms of capacity and the necessary equipment. Simply building refineries is going to take years, building it without Chinese equipment? Decades, if ever, considering the "Western speed" where they spend several years on boasting and puffing their chests before even starting to do any work.