I'm sure most people have already been totally convinced that disc brakes may be inherently "superior", even though economy cars and some trucks still resort to drum brakes at the rear-end. But it's worth consider how drum brakes retain a foothold on the heavy-duty truck market, even though it's most noticeable on models meant to feature off-road capability.
Among the reasons why I still see a lot of trucks with drum brakes all-around is they're often pointed out to be less prone to have its friction surfaces in contact with contaminants, which is a common issue on most rural environments. Then it turns out to question the suitability of all-around drum brakes for an economy car, considering not only the manufacturing cost which is still usually lower for a drum brake but also that not every farmer in countries such as mine may afford a medium-duty 4WD truck for instance.