You’re operating on the false assumption of scarcity. Supply and capacity of insulin is not limited in a meaningful way. Properly stored insulin lasts 3-5 months. A single bioreactor can make enough insulin for 1000 people for 1 month in one day. There are permanent bioreactors (picture a huge stainless-steel tank with tubes and everything) but there are also single-use bioreactors that are essentially big sterile bags that can produce almost as much as the permanent bioreactors but can be brought online in less than a week in an existing, validated facility.
Actual demand is unknown until it happens. Production is based on forecasts, which use historical data to predict future use, then updated as real use becomes historical data.
High-value, high-capital expense products like pharmaceuticals are re-forecast on a nearly real-time basis. They also run with a buffer that both minimizes loss due to expiration and maintains a buffer to accommodate surges in demand.
If every single American diabetic showed up tomorrow and bought a 3-month supply of insulin in their nearest major Canadian city, you’d have a point. That’s not what’s happening, nor will it happen. Even if thousands of Americans started regularly buying insulin in Canada, there would be no shortfalls, because the pharmaceutical industry can produce and distribute it faster than diabetics can consume it.
