Let's go with a nice capitalist version: A worker is underpaid when his or her regular expenses are higher than what they make in net income during the same average period.
This could not be farther from "capitalist." As a business owner I could not possibly care less how much your life decisions cost you. My only concern is whether the cost of employing a person is justified by the value they will provide, either now or eventually.
A worker is a human life whose value is independent of what they are able to produce, period.
Is it not obvious I am talking about a worker's output and not their value as a human being?
If the worker's output is not profitable for the company, the business should raise its prices so it can be profitable while still supporting its workers for their time. If the market does not support such prices, the business model should not be considered viable.
No. Please take note of all the restaurants in California that have closed in the last few months that found out what happened when they tried to raise prices to accommodate the increased minimum wage.
Rather than say "this worker produces $5/hour of output", let's phrase it as "this worker produces output for which the market now pays $5/hour". That leaves open the options to increase the rate the market will pay (marketing),
increase the worker's output (automation)
How about the machines that replace workers altogether so their wage goes to the true minimum wage of zero?
or to accept that the business as it exists now is not viable (reorganization).
This is a false dichotomy. It isn't "raise prices or re-org" The third choice is that the business can choose to limit production capacity to that which it can do profitably. There are businesses that do this.
I have yet to see an argument for why "business" is a good reason to lock people into a job that doesn't cover their expenses.
Who says they are locked in? Right to work goes both ways.
I fail to see how it is beneficial to society to essentially enslave people so an entrepreneur can pitch a product to a market that won't sustain it.
Whoever said society is supposed to benefit from anything a business owner does? A business owner operates a business to accumulate value for himself and no other. His goal is to be compensated for providing a service or good at a price greater than the cost to produce. He doesn't care if he hires people to do it or buys robots to do the same job. "Societal benefit" is the last consideration. He might realize a profit for providing a service or good that society views as beneficial but that is not the same thing.