Your train of thought has a gap. The boss has no monopoly on money. The customer has. He's the one that buys or pays something. The boss is, more or less, at the mercy of his customers. This is less of a problem if the boss sells something that is crucial to your life, like food, water, housing etc, so things you really need to survive, but a big problem if you sell something that isn't.

I respectfully disagree.

This analysis ignores bank and finance capital, which are the ones who hold the monopoly on money. So yes, it would be fair to say the boss (individual capitalist) does not hold the monopoly on money, but they have access to very cheap money.

If the individual capitalist didn't have access to cheap loans, and the supply chain wasn't propped up by neocolonialism (i.e. wealth extraction from other countries) then I would agree they would be dependent on the consumer. This had not been the case since the early 19th century or earlier.