I think a big problem is that short acting insulin, which was available 25 years ago, used to cost $9usd / 10 mL bottle now costs ~$80 with insurance (in california) or $200+ list price for an effectively equivalent short acting insulin. (numbers were from my insurance statements which include the cost for current prices, and from a family member who was on the pharma board at one of the large managed health facilities in california in the 90s.

To me, that cost inflation is purely artificial and not driven by any new tech relating to the insulin itself.

For T1 diabetics, the cost increases have been moving to insulin pumps which have infusion set costs in addition to the actual pump, and for continuous glucose sensors.