Zimbabwe was never the breadbasket of Africa. They were largely self-sufficient agriculturally and they grew a lot of corn and wheat but they never even got close to 10% of the food production in the region (with almost all if not all of their production being consumed internally).
Land reforms decreased Zimbabwe's productivity somewhat but more importantly other regions have become massively more productive with wheat and corn production on the continent increasing 4x over the last 60 or so years.
So they aren't and weren't ever really a "breadbasket". It's just everywhere else was largely unproductive and those regions have now caught up.
Zimbabwe doesn't really have anything to do with Cuba, either, other than also being a country that left the descendants of its European colonizers notably dispossessed after achieving independence. The tone of GP's rhetoric betrays a strong sense of chauvinistic grievance; it's not hard to draw a line between that and the sanctions and predatory sovereign debt arrangements that make anti-intellectual claims of cultural insufficiency moot.
It looks like you know what you're talking about, so I'll take that as true.
Wasn't there a case I vaguely remember from the British empire though when they loaded ships from what was then Rhodesia with grain and dumped it in the ocean, to stop prices falling through the floor (while, in other parts of the empire, people where still starving)?
Land reforms decreased Zimbabwe's productivity somewhat but more importantly other regions have become massively more productive with wheat and corn production on the continent increasing 4x over the last 60 or so years.
So they aren't and weren't ever really a "breadbasket". It's just everywhere else was largely unproductive and those regions have now caught up.