I severely question your conclusion that offshore talent and H1-B visa workers lower your personal salary by a huge amount.

It might be just pretty argument which is very useful for politicians and labor unions (or the like).

Actually the opposite can be argued. If those workers get a lot less, the team's cost as a whole drops, making room for paying you raise. Except for external factors like management just taking the cost savings and put them somewhere else. But then again, these savings could have been taken out of your paycheck ...