Sorry, my point was semantic. When you say someone is managing their own affairs, it is generally implied that this management if effective and successful.
Everyone manages their own affairs whether they want to or not, it's just that some do a terrible job at it.
As you say, African tyrants have generally not been either effective or successful.
BTW, IMHO most tyrannies are not nearly as effective as they appear to be on the surface. The classic is the incredibly wasteful Soviet system, but even the Nazi system wasted tremendous amounts of human energy and military potential. The most obvious example being their obsession on using transport to haul people all over Europe to the death camps rather than for desperately-needed military purposes.
Nations founded on liberty and freedom will always be the most efficient. The only reason they seem to be more wasteful and inefficient is that the population is aware of the waste and inneficiency that exist.