Apologies for the extreme simplification, but I think the time line assumed in your post is backwards: during the industrial revolution (and long after) there wasn't much of a reason to think about this, given the surplus of manual labor and fast technological advancements. It was not a very humane time.

You'll notice all successful corps have happy, hard working people, who believe in what they do.

They'll always eventually change into unhappy people with no cause left to work for.

That generally seems to happen because as soon as the company is successful, people see opportunities of getting rich and squeezing as much as they can from it "before its too late".

Ie the wealthiness of one seems to be worth making thousands miserable in their eyes. Since they're not directly making people poor and it takes some time I'm sure they don't even feel bad about it.

Of course, some people are better at keeping the ethical trajectory for a longer time and some companies are successful for a longer time than others.

I believe that the basic trigger for this to happen are called "free market" "capitalism" and "board of directors", "share holders".

It also means stuff will go up then down (and eventually up and down again and/or die). As human, we're pretty at good at going up/down in all areas.