Premiums are so high because the insurance companies can get away with charging that much, especially when they’re charging a large company and the individual doesn’t even realize how high the premium actually is.

Similarly, costs are high because pharma and healthcare companies can charge that much. An insured patient, past a certain point, is price insensitive, since their insurance pays the bill. So why wouldn’t healthcare providers charge as much as possible? Raising price does not lower demand. The worst that happens is the insurance company disputes it, but that process is post-facto and there is no mechanism to punish providers for overcharging, so they have an incentive to “shoot first, ask questions later” when setting prices.

As an anecdote, I knew a guy who ran a “compounding pharmacy” business. Basically he mixed together multiple prescriptions into one or a few pills, for e.g. elderly people who would rather take one pill than twenty. When the insurance companies asked him to price each pill, they had no reference for how much it cost — each compound drug he made was effectively a “new drug.” The insurance companies asked him how much it cost and he was literally able to name his price.