There's been investment in South Africa for as long as I can remember. At the end of the year, something like $350 billion leaves the country. Far more leaves the country in terms of profits than is ever given to any of the people.
If business really wanted to help, they could have paid their workers far more than they do. They don't want to help. They just want to keep making profits. And if you think business from outside South Africa is any better, you're extremely naive.
I don't know what 'other way' you're talking about, but 'business' has been tried now for at least 250 years. It doesn't work.