Beyond that, what is the incentive on the part of the company? No one is evaluating medications based on shelf life. Longer expiration dates -at best- do nothing favorable for the company, and at worst both reduce the purchase of more of the drug, -and- open the company up to litigation in the even it's dangerous. Why take that risk? There is simply no economic pressure to.
I don't think there's an economic pressure to have a longer shelf life either.
It's not any more efficient to stockpile drugs, and it doesn't make sense to do so, as your need for prescription drugs is likely not going to be multiple years.
