Shop will get 50%, supply chain a bit more, and the Chinese sweatshop under $1.
I think the real problem with this argument is that housing eats up such a large part of wages these days that a $5 saving on T-shirts is more than eaten up by rents and lenders. It's house prices more than anything which stop me and many of my friends from enjoying anything like the lifestyle that our parents had.
But, as long as inflation measurements includes housing, we really hide the true cost of globalization. We have relative deflation in the cost of good produced overseas and cheapened by labor arbitrage, but loose monetary policy is not evident in those diminished captital flows. Instead, too much money is chasing a stagnant supply of housing and inflates the value further.
Net, central banks target
inflation, globalization and labor arbitrage cheapen goods, while the lack of any globalization or arbitrage or supply drives the cost of housing up and up. In the end we balance it all out, and it looks like monetary policy is a very low-res tool.
But moved demand on T-shirt making elsewhere freeing up resources otherwise spent on expensive T-shirt making to focus on other demands.
The problem isn't how money moves around, it's just money, the problem is resource allocation.
Someone mentiones Henry George, he was on to something in viewing land as an important commons, something to derive rent for all from instead of insisting on labor as the only source of common wealth. (Also see Thomas Pain wrt to that line of thinking btw)
Thats disingenuous, you spend $5 less in total in your country.