I'll try and answer from my point of view.
Everything to major companies comes down to money. Companies relocate to other countries, such as India, because they will save so much money doing so. Companies don't care how it effects their current employees, as long as they see big profit they will do whatever it takes. They will lay off people and go to other places where it will cost them like cents and hour instead of dollars an hour to employ them. The standard of living is much different in countries like India compared to the US so they can only pay them cents or a few dollars an hour, opposed to people who work here where they will be paid much more.
I hope that helps you a little bit.