I grew up in reasonable well-off home in South Africa and attended this school
If you check this site, you will see that it's the 14th most expensive school in South AFrica. You will also see that my brother school (St Andrews College) is the 3rd most expensive.
Just like when you go to an Ivy League or certain private schools in America or in England or in Australia or in India, the rich send their children to these private schools (in the UK, they are called public schools).
So, essentially, I grew up with a lot of very people whose parents were - rich.. My brother went to Woodridge and Kingswood. Kingswood is the 13th most expensive school. I think he also went to Michaelhouse for a semester or two (he ran away). That's the second most expensive school in the country.
So let's just say that one doesn't go to schools like that unless one's parents have money. I simply grew up in those circles.
Also, as my late father had a successful business, I associated with the kids of parents who also had successful businesses as well.
I'm sorry you have never met these people, but I most certainly grew up with them in the 50s, and dated them in the 60s and 70s.