> Lithium reminds me of the story of aluminum, which too was only available via destructive and expensive bauxite mining

but lithium mining isn't expensive or destructive. Maybe you're thinking of shale oil mining?

Yeah, millitary tech has different requirements to civilian tech. Rugged, stable and reliable usually takes precedence over cutting edge.

Defence contractors who make pure custom millitary silicon will still market it for civilian use if they can find a market for it, its just unlikely that silicon that can survive extreme heat or extreme g-loads has a civilian market.