When people complain about high insulin costs, they’re complaining about new formulations that work much better. You can get the old stuff at Walmart for (relatively) cheap. The new stuff is probably under patent, although even when that runs out there are roadblocks for generic manufacturing - and that goes for every medication.

The fact that patent holders can draw out the process longer than they’re supposed to should be reformed, but that doesn’t get as many political points as capping the price to the consumer.