I think we'd have to start with how one would define a "living wage". I think MIT's calculator is probably a decent starting point, but it doesn't include government transfers, so it's going to fail to accurately describe the living standard for people that receive significant benefits like EITC or SNAP. Still, it's not bad.
Somewhat arbitrarily selecting my home county, I get a living wage of ~$10.50. That's about $1.50 below the median McD's cook wage, which suggests that you'd need to either receive a government subsidy, a higher minimum wage, live a very frugal lifestyle, work more than 40 hours (working 50 hours puts someone at $9/hour well above a living wage and it's not really that unreasonable), or hope for advancement (or some combination thereof).
I think it's a fine argument to make that someone in that position should either receive a direct subsidy or a higher wage. It also doesn't really seem that dire if a typical person can have the lowest skill imaginable job and can basically live OK (not great, but OK) by working a bit more than full time. As I typically reiterate in these threads, my position would be to increase direct subsidies via changes to either the EITC, another negative income tax, or a UBI.