The point is that by allowing more highly-skilled immigrants into the country, it enables many other companies to make use of that high-skill labor and increase productivity (which would increase our standard of living, in theory). The lowering of wages is only a side effect of that.
Why do the companies have to be in the US? Why can't they be in Mexico or India or Brazil - and US investors just invest in those companies and get the resulting dividends?
Why does the company have to exist in the US for us to get any benefits of increased productivity?
