The US does not have the cheapest electricity, but they have the money printer. Price is not a concern to the government, especially when it comes to war. The fiat system is built in such a way that it incentivizes spending as quickly as possible, which is the opposite of Bitcoin. Fiat was created to fund war, and as long as the money can be spent before it affects the market, those who print the money can buy whatever they want for the current market prices.
No arguments there but you are forgetting an important bottleneck which is the supply. ASICs don't grow on trees, which means even if they kept printing money to buy them to increase their hashrate they would still have to wait for shipments from China or start building the factories and come up with the technology that could compete with the existing ASICs which is still in Chinese possession.