$21 is an MIT-provided living wage number for many parts of the country (including Santa Fe, where I live (or close by)). There are places where that's still not enough: I think $35/hr just about covers anywhere in the US at this point.
It's also the CPI-adjusted equivalent of 1960s minimum wage numbers.
I used $2 in 1962 because in the 2016 Republican primaries one of the candidates made a reference to their job working in a burger store using these numbers.
I just Googled for "1962 mcdonalds hourly wage". It was much less than $2. Minimum wage was 1.15, and a Federal Reserve study called "Employee Earnings in Retail Food Stores, June 1962" says about 1.70. Also, cumulative inflation from 1962 to today is about 10.5x.
There is no single measure of inflation. There are multiple different ones, each with their own pros and cons and suitability for purpose. CPI is a common one, and that would put $1.15 in Jan 1962 at $12.09 in Nov 2024.
It's also the CPI-adjusted equivalent of 1960s minimum wage numbers.