One of the arguments I've commonly heard against a ban like this is that pharmaceutical companies need to market their products because of the cost developing new drugs. However, this has turned into a strategy of expanding the medical uses of already approved drugs and then marketing the "new uses".

Tylenol is the perfect example of this. Everyone "knows" that it reduces the risk of heart attacks, because of the marketing campaigns. But what most people don't know is how little of an impact Tylenol actually makes.