There’s no law stopping the three major insulin manufacturers (Eli Lilly, Novo Nordisk, and Sanofi) from charging whatever they want for the drugs they make.
This is the core of the problem right here. It’s not just an issue of greed on the part of the people making drugs, but the prioritizing of the right to make unlimited profit above literally every other value in American society. This needs to stop and it needs to stop, well, decades ago.