Breh it's a lil more complicated than that.
"At the time of independence in 1980, over 40% of the country's farming land was contained within 5,000 white farms. It was claimed that these farms provided 40% of the country's GDP and up to 60% of its foreign earnings".
"Over 3000 white soldiers who assisted in the BSAC takeover of the country were given land grants of 1,200 hectares (3,000 acres) or more, and black people living on the land became tenants. Later, Land Apportionment and Tenure Acts reserved extensive low-rainfall areas for black-only tribal-trust lands and high rainfall areas for white ownership, which gave rise to cases of black people being excluded from their own land"--From wikipedia
White people in Zimbabwe - Wikipedia, the free encyclopedia
The black people were basically relegated to the manual labor aspect of farming, not the agricultural, entrepreneurial, or even basic supply chain side of it. The white people owned and profited from the farms and blacks did the actual labor but didn't necessarily have the knowledge or tools to run the machine themselves. Of course this was intentional on the part of the colonizers.
IMO you can't really go 0-100 in a system like that by expelling all the whites w/o dealing with the steep learning curve that comes with it. Smart thing would have been to do a gradual transition process and phase out the colonizers at every part of the chain but I doubt the whites would go for that. All the sanctions and intentionally fukking up of Zimbabwe's economy didn't help either.