They certainly can be built elsewhere, however it's currently cheaper to import. It is very common to import when it's cheaper than producing domestically despi

They certainly can be built elsewhere, however it's currently cheaper to import. It is very common to import when it's cheaper than producing domestically despite it having a history of problems like shortages and fluctuating costs. Helium and rare elements(which aren't very rare) are some examples. Rare earth mines were shutdown in countries when China started undercutting prices.