> Slower progression is fine, by my standards, if it means people aren't suffering, or there's less of it.

Imagine what the environment would be like if we were still in the industrial revolution today. Hoo haa...

I also can't see how slave labour creates innovation. If anything, wouldn't it have the opposite effect? What's the point of efficiency when you can just throw more slaves at the problem? And think of all that wasted potential.