> given that there is no bigger customer than US government the companies might re-think their Burmese HQ?

Only if the percentage of their business represented by US government contracts is more than the US corporate tax rate, i.e. only for companies like Lockheed whose business is focused on government contracts. But those are some of the largest "domestic companies" being put at a disadvantage by the existing tax system because they already can't use the same international tax avoidance strategies as other companies when they're required to use domestic supply chains by those same government contracts.

Meanwhile the companies that do lower percentages of their business with the government would just stop doing business with the government at all, causing the government to pay more for things because that company would otherwise have been the one to get the contract by being the one to offer the government the best price.