The cost of labor is a huge part of the issue, but paying American workers less is a non-starter. When an American business hires somebody to work they must pay that somebody a state or federally mandated wage.
We call that minimum wage, although Right to Work states refuse to pay it, like Georgia for example. Even in Georgia workers must be paid so much an hour.
Waitresses there make about $2.50 an hour, no joke. That employer must also provide safe working conditions and worker's compensation if the worker gets hurt.
That is just the minimum for discussion; American employers are required to provide more than these three things. Now let's talk about Bangladesh.
Garment workers there make about $68 per month, no joke. These workers are making clothes for American companies to be sold in the United States.
There is no requirement there to provide safe working conditions or worker's compensation. If you were a business owner and only interested in profits, where would you set up your manufacturing?