When cars were invented, producing them in large numbers, operating them efficiently and comfortably would have been a major concern while anyone talking about safety would be ridiculed. As it turned out engineering challenges were sorted out by economic incentives but car safety/pollution control had to be legislated.
In case of cars though wrong design choices in older cars could be phased out eventually but in case of online platforms the choices will remain there for more number of people in terms of market penetration given the explosion social networks are having in the last decade. Even if vast majority of people prioritize other things over privacy, vocal and knowledgeable minority need to raise the concerns of the choices unknowingly being made by less knowledgeable people.