They tend to sputter when denouncing the very idea that Zimbabwe isn't just South Africa with a 14 year head start. Everything is so different!
I've finally figured out one relevant difference. The old Rhodesians had to work, hard and competently, for their wealth. They were world class farmers, and then during the embargo of 1965-1980, they built up their own industries.
In contrast, much of South Africa's economy is mineral, which generates huge profits with small skilled workforce; the mines wealth can paper over much shortfall in other parts of the economy.