Deleted member 109224
In Rhodesia, while it wasn't as bad as Grand Apartheid, "qualified franchise" was another means of denying the black population the vote. There were financial, educational and property barriers to the vote. This was complicated by the Land Tenure Act, which allocated roughly the same amount of land to blacks and whites. Except the white population was 5% of the size of the black population and got all the best land.
In South Africa, something like this could be the basis for extending the South African franchise over time no?
I think it's possible that by the 1970s TTL anybody who owns enough property, served in the military, or graduated high school were to be eligible to vote or hold office in South Africa. In the face of the decolonization movement, there'd need to be cessions over time. By the 80s or 90s this could mean a transition to absolute majority rule.