Saturday marks 12 years since the last federal minimum wage increase on July 24, 2009, the longest period in U.S. history without an increase. In the meantime, rising costs of living have diminished the purchasing power of a minimum wage paycheck. A worker paid the federal minimum of $7.25 today effectively earns 21% less than…
Lot of nuance here.
First item is that the cost of living differs from state to state, and even proximity to economic centers.
Second item is that some states already do that, and enforce a state level minimum wage, for exactly that reason.
Lastly, 1.5% of Americans make below the federal minimum wage. But to get a more accurate picture, we need to break it down by state, and compare to cost of living instead of minimum wage, which is going to make that proportion go up significantly.
https://nlihc.org/oor
This covers at least the first two items you mentioned.