Erm they arrived in this country with next to nothing and started selling shoes from the back of a bakkie.
Twenty odd years later they are - in your words - filthy rich, having scored scores of dodgy government contracts.

That is not normal business or a testament to their business acumen - they are corrupt to the core.

When businesses dictate policy and leadership appointments in a country, you no longer have a functioning democracy, you have a country run by a criminal gang.
That is present day South Africa, my friend.