On the same $90,000 gross, a worker takes home roughly R 17 626 more per year in South Africa than in United States. That gap reflects the tax structure alone — before rent, healthcare, or savings behaviour come into play.
Housing is the first multiplier. South Africa has moderate rent pressure, while United States has high rent pressure. That keeps South Africa's nominal advantage closer to a real-world advantage.
Healthcare and pensions go in the opposite direction. South Africa runs a mixed healthcare model — Public system is strained; most professionals pay for medical aid. United States uses a private model — Private, employer-tied insurance dominates; out-of-pocket costs can be significant. The country with lower take-home often shifts costs that the other country leaves to your private budget.
Net-of-everything, a relocation decision should weigh basic public welfare in South Africa against basic public welfare in United States, plus differences in pension capture, social safety nets, and city-level cost of living.