This is how every discussion on Errol Musk's wealth goes.
Someone makes an implication that they were fabulously wealthy, using abstract measures like emerald mines, or small planes as a substitute for a concrete measure of wealth.
Someone points out the value of both those things was actually quite low.
Then the goal posts shift to how much more money the Musk family had than the average family, which is true enough.
But they were still decidedly middle class. They all had to work for a living. And in American terms, there are tens of millions of households with similar wealth. Upper middle class, to be sure, but nothing unusual.
And the emerald mine, such as it was, is said to have been in Zambia, not South Africa.