The wages and lax environmental regulations are why the offshoring is cheaper.
The regulations that get used to prevent competitors from entering a market are usually “high standards” rules, like requirements that cost a lot to implement up-front, and prevent small players from entering a market. These are things like degrees required for hairdressers, or insurance requirements for subcontractors, or some kind of bond to get a license, or a share of a cartel, like a taxi driver’s medallion.
Environmental and wage and labor regulations do act this way, but people like these regulations because people like to breathe and not be slaves who get their fingers chopped off by the equipment. These regulations are a direct benefit to workers.
Offshoring seems, to me, to be mainly about getting around popular environmental and labor laws.
I don’t see how high corporate taxes affects offshoring. Your argument seems illogical to me. If the company offshores, and increases sales volume while lowering production costs, the profits would be greater, and the taxes higher. If they stayed here, their profits would be less, and the taxes lower.