The minimum wage is/was *supposed* to be for kids in or just out of high school, college students, etc.
The real cause of this, the point at which we jumped into the race to the bottom was in the 80's, when two things happend:
Union busting actually became popular. Reagan busting the air traffic controllers, and the unexpected level of approval from Americans, was a tipping point. Upward pressure on wages fell away across the economy.
Supply side economic policy has been the norm since (under Reagan) taxes on the super rich was basically cut in half.
Income inequality is the real devil here. The flatter the line is the better off everyone is, even the super rich. To fix it we need two things, upward pressure on labor wages, and an artificial friction to acquiring wealth. By that I mean the more wealthy you are the harder it is to get more wealthy. A progressive tax system does this, but maybe there are other methods.