then to repatriate those funds wouldve required them to pay the U.S. corporate tax rate,
As far as I know, in general, the taxes paid to a foreign country are a credit toward taxes due in the United States. This is also true for your state taxes, i.e. taxes paid in another state are a credit toward you state taxes.
So there are other issue involved here besides the taxes.
If the foreign tax rate was 20% and the US rate was 35%, they'd still owe the 15% difference to bring the profits home.