followup question - outside of agriculture - Once the industrial revolution got started, why were there not factories full of slaves doing all the repetitive low-skill labor?

There is lots of repetitive low-skilled labor in that meat packing factory in Upton Sinclair's The Jungle. While that book was a generation too late, was factory work too prone to expensive sabotage by disgruntled - that is to say nearly all - slaves? Is there some aspect of capital markets that can spend all the scarce money on either human capital OR all the equipment? Were the increases in productivity inconsistent with people remaining enslaved? Was it all down to slavery becoming expensive after the international slave trade effectively ended...which by coincidence was when steam power technology improved, so that now we completely misunderstand the causes and effects? Was it really abolitionists persuading humanity to do the ethical thing?