I was just thinking about this over the weekend. Two differences: 1) the speed with which wealth is created now and 2) most of the robber barons created or financed things. The historic robber barons had decades to create their fortunes and many were from impoverished families (Andrew Carnegie, Jay Gould, John Rockefeller, etc.). Their desire for wealth at any cost propelled them to great heights. We still have physical evidence of the world these men built — what will remain of the recent tech innovators? Their legacies await.