That assumes that there is no diminishing return on additional hires. If I run a warehouse that generates $100,000/mo with 10 employees being paid $1000/mo and those 10 employees satisfy the needs of the warehouse, I wouldn't hire more for fun.

There is some finite amount of demand that needs to be processed by the warehouse, the fact that I can satisfy that demand with a small number of low paid workers doesn't somehow increase the demand.