What if the guy who owned the field gave the workers 1 potato a day, but charged them 2 potatoes a day to rent the potato bag, to buy their meager food, and to sleep in the company shack at night?
And if they tried to leave he charged them for all the back potatoes they owed?
Sorry, it was horrid working conditions at the time and all perfectly legal. Unions were needed to make the playing field fair to workers.
Under your example, why would anyone take that job? People have the ability to vote with their feet. Some other farmer would offer a better job and squash his competition. A labor union isn’t needed to correct that problem.
The industrial revolution did not create horrid working conditions, did not create rapacious owners, nor did it create child labor. It simply brought those same practices from the country to the newly created cities.
Unions did NOT improve anything. It was the increase in wealth, from greater productivity, which allowed a politically stronger middle class to form, allowed greater leisure and choice, more opportunities for education, and allowed the creation of the concept of “childhood” (invented by the Victorians)