The capital-labor thing is a simple example of "you cut and I choose." The capitalist decides how stuff will be made, and the laborer gets the first dollars of revenue from the enterprise. That's the deal. The capitalists gets what's left after the labor has been paid. The capitalist takes the risk and, for that reason. calls the shots.

The only issue is how many of the first dollars of revenue the workers will get (including any expenditures to make the workers safe and/or comfortable). That amount of pay and the nature of such expenditures are bargained for, at the workplace and in the legislature. Some employees do quite well - well enough to become capitalists. Others do not. (An awful lot of our capital is held in pension and retirement savings plans.)

I've never seen a Marxist talk about the role of risk in defining capitalism. (The word does not appear in this essay.) But risk is what makes capitalism capitalism. Ignoring it sends Marx off into the wholly irrelevant explorations of the sort described here.