And don’t forget who most of that cash would go to.
Frankly, there is the argument that all of this tech and optimization was there for others to develop but no one cared that much and its only now after you and others realize how good it is that you want to just go in and take it "because its so vital to national security".
Furthermore why can't someone just copy them? Drop a ton of money on poaching their engineers and just copy whatever the government needs?
Clearly leadership at SpaceX including Musk are a driving force behind this being so good...just look at the trash all the other companies are peddling. The magic might just go away if its nationalized and if it does then you probably can't just go "oh sorry bro heres your company back pls give us more magic".