I guess I'd qualify as the South African's you are directing this post at.
So I'll start with why I left.
Reason:
There was no institutional support for my entrepreneurial ambition. I did not qualify for any government grants because my business was either in the wrong sector, or my economic standing was too good (comfortable life, not enough to fund a new business tho), I did not fall under BEE or any of the related funds.
So I left for Canada, to grow my business, and have better access to resources, not just funding, but people, experience, business incubators etc.
I did not leave out of fear of crime, economy or any other listed reason here. Not saying that these don't play a role in someones decisions, but they weren't mine for leaving.
Would I return to South Africa?
For a holiday and to see my family, sure. To live and work - no. Why? The quality of life in Canada far exceeds anything I have experienced in South Africa. I miss my friends and families, but beyond that, there is very little else that South Africa can offer me.
(I do not have any family in Canada, and did not know anyone when I first moved here)
It's not even about the safety, or crime that makes the quality of life here better. The access to working infrastructure, public service and support - medical/professional/education/public parks - is far superior.
Which is really unfair to compare. South Africa and Canada cannot be compared, nor can South Africa and the UK. The issue is that South Africa is not a first world country, and it would take time to get to a point where people are willing to sacrifice what they have, to go back to what they had.
This doesn't apply to everyone though. I have met many a person who loves South Africa, more than they like the quality of life a first world country offers. So its an emotional decision for them. Or maybe its a decision to return to family/friends etc.
That simply is not me.
Realistically, the only way for me to consider moving back to South Africa, is if the issues raised in the top comment by /u/Godsux is addressed. But then it's still not a simple, "Sure, I'll move back". It's something I'd be more willing to consider over the current state of the country.