It’s not jobs so much as entire industries that have moved overseas. Taxes as well as the regulatory environment are the underlying reasons. Those are the jobs that you find moving to China & ‘underdeveloped countries’.
A corporate exec is looking at his bottom line. He can either:
A. Automate to increase productivity, or
B. Move offshore to find cheaper (less productive) labor.
Neither is ‘cheap’ or cost-free in the short-term.