Why would employers want there to be large numbers of unemployed workers?

this is in the 19th century industrial revolution, i might add. thanks!Why would employers want there to be large numbers of unemployed workers?
The more unemployed workers, the less employers have to pay.





Lets say there are 10 jobs and 100 people want them. The employer can pay a very low wage and still fill those jobs.





If there are 110 jobs and 100 people to fill them, then employees will go to work for companies that pay them more.Why would employers want there to be large numbers of unemployed workers?
Its the same reason companies outsource to china. cheap labor. When there is a high amount of workers and not so many jobs then the workers will work for lower wages and less benefits. The china example is a little more complex though.