Don't tell them that because then you won't be able to get vitamin c in a pill form without a prescription. By the way that has happened to other readily available products before. For example red yeast rice was a fermented form of rice that was fermented with red yeast which produced a molecule that was supposedly effective for heart disease. When a major pharmaceutical company developed a drug that produce the same molecule they actually had red yeast rice or rather fermented red yeast rice removed from store shelves all over the country even though it had been readily available as a natural supplement for years and years and years. In fact now the version of red yeast rice you can still buy on the store shelves is not fermented and does not contain the molecule which was the original supposedly beneficial effect of red yeast rice and why people would buy those pills. So to take a readily available product off the shelf is not unusual and it's happened before.