No, the vials were usually available, but the doctors get pushed to push the new delivery devices (like the insulin pens, which have still stuck around). Insulin (with insurance) is generally cheap enough that most can afford it, but without insurance the amount they try to charge you is insane (though programs like the goodrx or whatever that pharmacies use if you don’t have insurance bring that down to a sort of affordable amount… sometimes). I don’t know the exact details of the business of insulin, but producing the stuff is finicky enough and startup costs are heavy. They use modified E. coli (or maybe S. cerevisiae? It’s been a while since I’ve looked at the biotechnology… often bacteria are easier to genetically modify but the eukaryotic yeast is more likely to have an internal environment that matches so protein production is better… off the top of my head that may be the difference between novo nordisk and eli lilly, the two big producers of insulin right now) in giant systems that produce the insulin. That’s a lot of investment and testing to get up and running to standards (or maybe it used to be… now maybe you could just slip the fda a bribe in a envelope at the same time as you give orange man one).

Now the money is being made by the insulin pump companies, who have high costs for the supplies you continuously need for them. The insulin itself still come from the old vial and is drawn out by syringe… which can be proprietary, jesus christ they do stupid things to a simple syringe to force you to pay them for the way to draw out the insulin, just look at the stupid thing that you have to deal with for medtronic, one of the bigger diabetes companies.