No it's not. Essentially you are saying it's ok to have an "expiration tax" and that it doesn't change the market. I'm saying the expiration tax does change the market, and raises the cost for the consumer, even if it's factored into their purchase. Typically consumers don't have the ability to substitute complements, and manufacturers products are patent protected, so it's another way to raise prices and increase manufacturer profits.
I explicitly point out in my original comment that this applies for monopoly markets! To spell it out in gory detail: in a simple monopoly, the price is that which maximizes the supplier surplus for a given demand curve, and the demand curve will be proportional to probability that any single pill is consumed. If you have a more complicated model, then by all means explain it to us, but do not just assert the contrary with no explanation.
