These have had the desired effect. The Apartheid regime has fallen. This was a necessary step, but the next phase is even more important. Many Unviersities and schools in the US and elsewhere were at the forefront of the sanctions calls. This didnot require much personal sacrifice on the part of the students, the universities or even American business.
Oranges taste very much the same wether they came from Apartheid South Africa or from Australia.
Sanctions, though have left South Africa destitute. An enormous number of young educated South Africans have departed for better paid, more stimulating positions in other countries. Maybe you have some in your school or university. What is needed now is reconstruction. This is not going to come without education.