hmm this is an interesting point. Thanks for raising it.
e.g. the workers producing bread make 10 bread each per day but will only buy according to their demand which is basically always less than that (though never less than 1). However on the monetary side, essentially the money just flows back and forth between you and your workers, so any "profit" you make means you are charging more for goods (based on their demand) than you are paying your workers. So At any given time either you are losing money or your workers are so it is a bit of a balance.
This is all true until you get access to gold and then can produce more money. In which case it is possible for both you and your workers to be making money at the same time because you are digging it out of the ground. Though perhaps in real life if rate of monetary production far outpaces the prices of goods, people would just stop working since they no longer need to work to buy things. This doesn't happen in this game as employment rate is as high as you decide.
I'm curious what you would change about the game to better match your expectation.
FYI I'm working on a Command Economy 2 which will have a significantly more complex economic/social system that will hopefully account for surplus-value-type interactions.