The UK actually had a similar requirement in place until 1971. However, it could be legally circumvented by simply using a radio not hard-wired into the vehicle's electrical system. Many would simply mount a battery-operated transistor radio to the dashboard. This likely would have tended to be a popular option anyways, as hard-wired radios were not standard features and I imagine may have only been available as relatively expensive aftermarket add-ons in some vehicles.
As per the article, "Exemptions are available for motorists without a radio receiver, provided they sign a form to that effect with the public broadcaster. With approximately 1.2 million vehicles in Zimbabwe, the levy is expected to generate millions of dollars for ZBC." I'm not too familiar with the vehicle market in Africa, but presumably their new and used vehicle market might contain a significant percentage of vehicles where a radio is not equipped from the factory or has been taken out to be sold at some point.
Furthermore, more "under-developed" countries have much higher percentages of people who either don't drive or drive motorcycles (usually with no radios equipped) for transportation, so it's not really the "huge" silver-platter revenue generator that it would be in more car-centric societies or even countries that are wealthy but more transit oriented, such as The Netherlands or Germany.
Last edited by tdotwriter (Yesterday 8:04 pm)