Built on steel and state planning, the Vaal Triangle once symbolized South Africa’s economic future. Today, its residents are living through the long aftermath of deindustrialization. Cold November rain turns Toto Street in Sebokeng township into mud. The road, like most here, is unpaved. Diluted sewage seeps between the small houses behind brick walls and sagging fences, past a general dealer under a corrugated roof, through scattered rocks and…