When you switch a 11 year ICE car with an electric, yes, you would generate a 11 year-old ICE car. If priced low enough, somebody will pick it up and use it for a few years, since the purchase price, compared to a new electric car, is lower than the (worse fuel economy + higher maintenance costs) figure.
But, unless gasoline and diesel drastically drop in price, you are running towards an economic wall, since it's exactly people from Africa and former soviet territories that are the most sensitive to fuel economy and high maintenance costs. Meanwhile, electrics drastically drop in price, since they simpler and cheaper to produce.
The extra few years European cars will see in Africa is just the long tail of the ICE car in Europe, not some fundamental shift. If those would not be available, Africans would purchase cheap new Chinese ICE or other low cost brands. A visit to Eastern Europe will convince you that some 50% of cars are newly purchased cheap brands like Dacia-Renault, Mitsubishi Colt, Chevrolet Spark, often stripped down versions made specifically for these markets and priced at something like 10.000€.
These will have an even lower life expectancy than the typical 20-40.000€ western car, and will be in need for replacing.