That's the history of "Africa's four decades of independence in a nutshell", says David Blair, Africa correspondent for the London Telegraph.  Julius Nyerere's 24 years as President of Tanzania is a case in point.

Assuming power after Tanzania gained independence from Britain in 1961, Nyerere promptly implemented socialist economic policies with predictably appalling results.  Against all evidence of economic history—and advice from people who know that history—he collectivised his country's farms.  Virtually total economic destruction followed in due course.  Before independence, Tanzania was Africa's largest exporter of food; by 1976, Tanzania was the largest food importer.  (Now where have we heard that again recently?)

Undaunted, Nyerere proceeded to nationalise everything in sight, and Tanzania accordingly became an economic basket case.

By the late 1970s, Tanzania was a collapsing, chaotic shell, where the shops stocked almost nothing and even toothpaste was virtually unobtainable.

Dar-es-Salaam has never fully recovered from that era. The potholed, shabby streets look as if they are stuck in a 1970s time-warp.

Nyerere, to his great credit, recognised that he had been responsible for a catastrophe. He stepped down voluntarily in 1985, after a mere 24 years in power, and publicly admitted his failure. Thereafter, he devoted his life to good works. His successors opened up Tanzania's economy and welcomed western aid. Today, Tanzania is normally cited as one of Africa's more successful countries.

Another scene from socialism's sorry record of consistent, ruinous failure.  Yet some people never learn.