> The only "risk" of corporations "taking their ball and going home", is if the United States pursued a transparently self-destructive tax rate on foreign-based corporations. Which there is absolutely no reason to expect would even enter rational conversation.

What's more likely is that corporations would split into the global corp, and the US corp. The US corp pays the high taxes and does work in the US. The global corp owns all the IP, and leases it to the US corp for some amount of money.