First of all, it is SO difficult to actually get a visa ( they have a "LOTTERY SYSTEM", where you have to BUY a ticket for each person, and then they draw "winners", every time you want to get one ) that the cost can be prohibitive.
Secondly, it is almost IMPOSSIBLE to fins a nation that WILL take them in! The USA, the UK, and now, even Australia aren't good bets at all. So just WHERE are they all to go?
The Rand is so devalued AND there are terrible restrictions on how much one is allowed to take out of RSA, that that is also a double edged problem.
And what about selling their property? Oh oh....yet another "problem"!
And last, but certainly NOT "least", for many Afrikaners...this is THEIR nation; their families have been there longer than ANY American family has been here! So they dig in their heels, tell themselves that:"this is MY land, MY country,I'm staying" and so they stay...hoping and praying that things will get better and IF it comes down to fighting, they are more than willing to fight to the last. They've done this before, if you don't know.
By all means DO ask those who actually know and understand the situation there. And, IF you are truly interested in this topic, then DO read some of the RSA newspapers that are on line.
I'd suggest some books to read; however, many of them aren't available in the USA.
By Indians, if you mean those who call themselves "coloureds", there, many of those families have been there for well over 100 years and it's their "HOME". Some have banned together and formed a separatist group of their own. And NO, the blacks don't like them either!
All of this is far more complicated than you know and I've only given you the very briefest of answers...hitting the major highlights and not even talking about daily living conditions, the horrible laws & regs & the state of corruption that is frankly unimaginable to Americans.
The following information is based on the fact that around 50 years ago, my late husband escorted a South African labor leader around the country for 2 weeks. I met and talked with him several times, and my husband shared much information he learned during their travels. His position in RSA was similar to the head of the AFL-CIO at that time. It was long before the liberation of African lives there. He spoke English, not Africaans (Dutch), so his position was rather delicate. Colored were people of mixed African and white matings. The Indians (from India) were a separate matter altogether. During his time there were severe laws against such mixing, so he described one time when he suddenly realized he was home alone with his African or Colored maid, and immediately told her to go home, with fear that someone might denounce him.
Also during that period we had an Indian friend from Bombay (Mumbai) who told us he could only take $10,000 dollars out of the country. You mention that RSA has similar restrictions today. Obviously, if you can make someone too miserable, they may sell their property for a song just so they can leave if they can get a visa. Trump wants people from Norway to apply to US, but Norway has a better social safety net and schools than we do. Perhaps he would do better if he could persuade RSA to let some of their unhappy white people become legal US immigrants.