Please don't export US labour and safety standards. The amount of paid time off is hard to argue is not unethical, the conflation of vacation time and sick time clearly is unethical, the amount of parental leave (especially maternity) is a crime against humanity. The firing procedures are also something you'd expect to read about in a history book besides a picture of a child visibly yearning for the coal mines, contracts with a mutual resignation period giving both parties adequate time to transition is a bare minimum. And that is just the tip of the iceberg. Please please America spend serious efforts developing your labour standards to a humane level instead of exporting them.

Abolishing restricted borders, collectively would push the logic to its final destination. Such sweat shops exist because humans are confined.

Cross border inspectors is mostly PR theater. Even if it was feasible, local verticals spill into others, so it would always be lower costs in less developed/regulated nations.

That's essentially colonialism. You can't go into other countries and change their labour laws, it's a violation of their sovereignty. Obviously there's a huge problem with uneven development across the world that makes outsourcing possible and difficult for workers in the developed world, but I'm not sure such a solution would be politically feasible.