The reality is that there is a big divergence in Johannesburg between the wealthy and everybody else. The people that have nice housing live behind tall fences with barbed wire and many have guards on duty 24/7.
Many buildings in the city center have been abandoned and are occupied by squatters.
Many others live in an areas like Soweto, which is an acronym for South West Town. The homes here are tiny structures built of scrap metal and discarded lumber. Things like plumbing, electricity, and running water do not exist in these homes and living conditions are deplorable.