For instance, with the manufacturers of insulin, none of them are American and they offer to sell the insulin to everyone at the same price.
The problem is that the large insurance companies use just three middle-men drug buyers called Pharmacy Benefits Managers (PBM) who DEMAND growing discounts every year from drug manufacturers, so the drug manufactures have to raise the prices to the US market every year to keep making a profit.
Novo Nordisk is willing to sell insulin much cheaper, but the drug buyers demand about a 75% discount off of the wholesale cost or they'll make the product not covered by the insurance companies they represent. To compensate, they raise the wholesale price in the US so after the forced discounts, they still make the same amount of money.
The people who suffer are the ones who don't have insurance.
The solution, at least in the case of insulin, isn't cheaper prices from the manufacturer, it's for the US to pass a law that prevents insurance companies from dropping a product based on the refusal to discount the product if it's under a certain price-per-month.
This article seems to cover the finger-pointing between the manufacturers and PBM's and insurane companies very well: https://www.healthline.com/diabetesmine/pharmacy-benefit-man...?