Yes, had the US income distribution and US standards of decency remained exactly what it was in 1968, the minimum wage would now be $21.16 per hour.
I grew up on the idea that America stood for progress, continual progress toward a better society. Even a $21.16 minimum wage wouldn’t represent progress. It would mean socially standing still, just with better technology and higher productivity levels. Progress would mean a minimum wage in excess of $21.16 per hour.
Of course, a minimum wage in the mid-20s is politically inconceivable. But it is technically, economically, and socially realistic. The only reason we can’t have it is the greed of those at the top and the intransigence of those at the near-top. The only reason we can’t have it is that we don’t want it.
We are not the Americans of 1968.