All business taxes and regulations could be eliminated entirely and that would do nothing to change the fact that foreign workers would still work for a fraction of their American counterparts.
You're right. But if you apply reason to what you just said, you made a great and accurate case for deregulation. Before regulation, the tradoff is:
Positive: Cheaper labor, broader workforce overseas...
Negative: Culture/language of workers, different time zones, ...
So, with high US regulation you make the reward of escaping that even higher and more worth dealing with the negatives of offshoring. The way to keep American business here is to make it appealing to stay, not put up obstacles to leave because they will figure out ways around that.