Same with minimum wage. Whites were tired of blacks underbidding them, so they just outlawed their jobs by making unskilled labor valued below X illegal.
"Minimum wage legislation emerged at the end of the nineteenth century from the desire to end sweatshops which had developed in the wake of industrialization.[17] Sweatshops employed large numbers of women and young workers, paying them what were considered non-living wages that did not allow workers to afford the necessaries of life." ...
"The earliest minimum wage laws in the United States were state laws focused on women and children.[25] These laws were struck down by the Supreme Court between 1923 and 1937.[25] The first federal minimum wage law, which exempted large parts of the workforce, was enacted in 1938 and set rates that became obsolete during World War II.[25]'
We know your scenario isn't true because there are plenty of white-owned businesses which knowing hire undocumented workers in order to pay them sub-market wages with poor working conditions.
Go back further. Minimums were applied to the railroad in 1909, pulling them up to the prevailing white wage when the Brotherhood of Locomotive Firemen became enraged blacks were working for cheaper.
I don't see anything about a minimum wage. I do see 'the arbitrators did rule that the railroad would be required to pay African American and white firemen the same wage' but nothing about how that minimum was set by law.
Minimums for a union job are not the same as minimum wage, which is the legal minimum set by law.
Union minimums predate the Civil War. For example, the Boston Journeymen Bootmaker's Society had a minimum price per shoe made, back in the 1830s, leading to Commonwealth v. Hunt.
Well back in the early 20th century I'm afraid that was mostly what was available to discriminated minorities. It's not just theory, it goes back to railroadmen being pissed blacks were undercutting them. They could not just outright outlaw blacks so they just got the minimums set to the prevailing white wage.
Suffrage in the early 20th century applied more to whites than blacks. And having low wage labor be black market without protections can in some cases benefit the upper classes.
