It's squared by the employees wanting the maximum pay for the least amount of work. It's call "Supply & Demand". It's the Law.
> impossible for an individual to push against and win anything that is contested
Not impossible at all. I've done it many times. The power the employee has is to say "No" and go work for someone else, or start their own company.
> Like 80 hour work weeks / children working / unsafe working conditions
were necessary when productivity was much lower than today. It's no surprise that those went away when productivity increased. I can't even think of a job a 10 year old could be useful at in a modern company.