Mining is all I've ever known, My ancestors lived in a system with high radiation hazards during the colonial expansion era, and having lived there for so long they evolved to tolerate it creating a subspecies of humans. Because of that when similar systems were found, corps would generally inquire for workers from them.
Making mining, development, and terraforming jobs very profitable for those systems. Therefore bringing wealth back allowing them to reinvest in the old terraforming equipment. --