>>The "goal" of a low wage job is for an employer to make a profit from someone else's labor

That is the goal of all jobs, high, low, middle

Employers are not charity, they do not employ people so they can have a good income.

Employers employ people because they need work done to make money off that work, the second you cost your employer more than they make off your work you are out of a job.

Sometimes that cut off is more direct (i.e if you make widgets your per hour the rate of manufacture can easily be factored into the cost of making the widget) but if you some do something more nebulous like cleaning the floors, or filing papers, that can be harder to calculate but every business does.

That's right, but we don't have a society unless people have incomes so maybe this isn't a good model for funding a civil society?

This is not the case - there's plenty of civil societies that have existed over the millennia that are subsistence economies. They aren't wealthy, but that isn't the point.