Racial discrimination aside; there are clear differences between social-economic, educational, crime, etc... levels between the whites and blacks in SA, just as you can find such differences in many countries between different ethnic groups.
In South Africa's case it's to a large part a result of apartheid; and just the fact that the whites always had access to privileges, businesses, education, etc... while what was left over was thrown to the far more numerous blacks as a sort of bone to fight over.
It's also clear that management of the country has gotten a lot worse (excepting apartheid policies naturally); just as it did for example in just about every newly independent colony that fought off colonial rule in the 2nd half of the 20th century.
Does that mean that those countries shouldn't have fought for or insisted on independence? That they should have kept the exploitation of their natural resources, discriminatory policies biased in favour of white settlers, and inability to rule their land according to strictly their own interests - in return for good management courtesy of the political elites of the European empires and relative stability they offered?
When India gained independence it rapidly descended into a huge orgy of ethnic cleansing not seen in the world since, and dismemberment into a number of different countries. Many of the conflicts that were kept a lid on by the British, such as Sri Lanka or Kashmir - are more troublesome today than they ever were in the days of the empire.
But that's the price of freedom; the grievances of these different peoples were only kept in check in the first place because the British established favourites and ruling classes amongst them; these very same conflicts were a result of British rule, not just kept in check by it. Or in other cases everyone was simply commonly unhappy with British rule and thus had cause to unite while under it.
The closest analogy of South Africa is probably the Bolshevik take over in Russia, 1917. Where the overwhelming mass of illiterate peasents and barely educated urban working-class and military conscripts took power from their own country's upper classes.
The whole country ended up in a civil war for several years, crime was very commonplace for years after, and a lot of unneccessery terror, bloodshed, economic mismanagement, famine, etc... happened simply because those very same people who revolted - had no idea how to run a country.
South Africa is now being ruled by more of its population than ever before and that's a good thing, whatever the difficulties encountered in the process.