Earlier quoted context omitted.
They used slave labor too, don't forget!
Slave labor is most efficient when it comes to non-skilled, hard work. Mining, agriculture, sex (where it still survives even in the Western world), where the output is easily checked and counted. When it comes to anything sophisticated done by qualified people, like "making advanced tools for the Führer", the options for subtle sabotage are there and pissed-off people will use them. In general, German occupation aut…
And yet, we invent things like the cotton gin, "enabling much greater productivity than manual cotton separation", patented in 1794.