We can only say that a company and a prospective employee have equal leverage, and thus achieve an actually-fair deal (in a number of senses, but not all senses), if they actually have equal marginal/proportional consequences for not taking the deal.

For low-skilled workers in a work-or-starve environment where employment is scarce, that means that the executives of the company will potentially be out on the streets begging if they do not hire the worker.

Minimum wage, however, among its many other effects, can close some of this leverage gap.

Now of course, there are ways of managing this while retaining markets and capital, but not if you accept Capitalism as a morality in itself.