That used to be true. The US switched to taking an aggressive captivity approach to its strategically important corporations. That changed when Pfizer tried to flee to Ireland in an inversion due to high corporate tax rates.[1]
Apple, Cisco, Intel, Microsoft, Google, Walmart, Pfizer, Amazon, Amgen, Merck, Facebook, Qualcomm, AT&T, Verizon, JP Morgan, Bank of America, Wells Fargo, Citigroup, Exxon, Chevron, Berkshire Hathaway, Visa, GM, Ford, Disney, Comcast, Procter & Gamble, etc.
If any of those companies attempted to leave the US as their corporate domicile (whether to Canada, Ireland, Mexico, Japan, or China), they would likely be blocked by the Treasury. They'll change whatever rules are necessary to maximize the pain. There are a few exceptions to allowing companies to leave. Germany for example, via Bayer, was allowed to buy Monsanto - which is a strategically important corporation - because they're an ally and it's expected that when the US wants to buy an EU company there will be reciprocity (eg the failed NXP Semiconductor acquisition).
Smaller companies may slip under the acquisition restrictions for countries not named China (or Russia). For example AMD would be allowed to be acquired by a tech company from Canada or Britain. Celgene or Regeneron would be allowed to be purchased by Takeda Pharma.
[1] https://www.washingtonpost.com/business/economy/pfizer-aller...