Media blasting is a term coined in the very recent past. Prior to the 1990s, the process of blasting with abrasive media was more commonly, and more correctly, called sand blasting. Back in the early days of blasting, the predominant abrasive of choice was sand. Silica sand is the more appropriate name, based on the fact that common sand is primarily comprised of mineral quartz, which itself is composed of silica and oxygen. Silica sand was used because it is cheap, readily available and effective for many applications.
These were simpler times when cost and results were given more weight than the health and safety of those exposed to it. Seatbelts in cars, for instance, were not required in cars and trucks. Cigarettes were not considered dangerous. I still do not remember wearing a helmet while riding a bicycle until well into adulthood – simpler times indeed.