OK, so I am diabetic, I am not yet on insulin but I do know a little about it so here is the short story.
Here is a short history of it's development:
https://www.diabetes.co.uk/insulin/h...f-insulin.html
Here is what insulin really costs:
https://www.goodrx.com/blog/how-much...ompare-brands/
Short answer, people want the latest, greatest, easiest to use, least to think about insulin and to be able to not have to think about their diet when using it, so they pay through the nose for the super sophisticated stuff in the auto dispenser with the auto tester that has bluetooth connectivity and so on. People then complain about the costs and surprise, surprise, surprise, politicians make hay picking the highest cost of the newest product to make extremist claims about how unfair it is.
This doesn't address the issues with the fact that it's harder to make than almost all other drugs, it goes bad fast, there are patents that took decades and billions to develop that the owners defend and that there are only so many ways to bioengineer a medication to simulate/replace a pretty common human chemical. The best bet to ending the insuling price problem is research and development of artificial pancreas but hey, paying for research doesn't buy as much votes as welfare so you know which way the US government has gone since the 70s.
If you are willing to control your diet, test your blood and pay attention to the warning signs of being an idiot, plain old injectible insulin works well and is a lot less expensive and most companies have programs where you can get it with a discount or copay card or free.