These people making things in slave camps won't be happy doing it for ever. They will eventually wise up, and start protesting like we did in the 60s and 70s to get more money and better conditions.
Japan used to be a cheap place to manufacture, but eventually other countries industrialised and undercut them. The Japs are still getting over their 'lost decade'.
Even the mighty China is suffering because of problems in the Eurozone and other economies. There's even property bubbles building up there, that could all end like our property bubbles.
Where to go for even cheaper labour?