Your argument doesn't make any sense. If the insurance company is paying for the drug then they would rather pay $50 than $75 for it. If the person has a deductible, it is conceivable that they would forgo treatment if the price is $75 but not if it is $50 because they didn't think they would use up their deductible, but then they ended up using it up anyway. The insurance company would then save money. But this doesn't seem like it would happen often enough to make this a good bet for the insurance company.