It should also be noted that this growth was completely unprecedented. From that graph it looks as if, “oh, there was some growth in the 1800, but nothing extraordinary”. But if you’d continue the graph back to say 1700, it would have been flat until the late 1700s, then shooting up in a hockey stick.
It is also interesting to look at some of the anecdotal evidence of how the 19th century was filled with innovation that made the average persons life better.
And it is important to be aware that much of the 20th centuries growth was in a way an aftereffect of inventions that were made in the 1800s, e.g. petroleum and cars.
It should also be noted that the laissez-faire era was remarkably peaceful, while the Progressive era saw this explosion of violence.
Clearly, if average GDP went up by multiples, it couldn’t just have been white people getting rich at the expense of blacks and indians. I’m not saying they weren’t disadvantaged, but their standard of living went up too. And if the lacking performance of those groups shows anything, it is that not being able to participate in the market is really bad for you.