No, they often do so because they don't want to pay the rates demanded by US-educated engineers. The education bubble affects more than just the people that take on the debt. Their demands for a salary that can maintain and pay off that debt affects US businesses. It's a competitiveness issue.

Often the reason a firm will outsource the position is to save money and have a level of labor control that would be illegal in most states if the worker were a citizen and employee instead of foreign contractor.