The US is an extreme example of a system that optimizes totally for choice...and it achieves that aim. The UK is an extreme example of system that optimizes totally for access. They both achieve their aims but there is a necessary cost. The most successful systems are mixed ones (Mazzucato is prone to make extremely reductionist statements about this: the private sector has this disadvantage, the solution is all public...in the UK, we know this doesn't work...we have tried it).
I'm not sure this is true, or at least, I don't understand what pre-requisites for this to be true the U.S. posseses. Insurance is not allowed to trade across state lines, the private marketplace has a small selection of plans, most people get their insurance from their jobs meaning they only know the details of their medical plans AFTER a non-trivial time down payment (in other words, the transaction costs are high)
I think the criticism that the U.S. system doesn't really have that many positives is a fair enough assessment.
Have you been to a place that doesn't optimise for this? The US is one of the only places in the world where if you are sick, the medicine (if it exists) is 100% available.
I have a relative who lives in a place that doesn't have this aim...she is sick, medicine exists but "policy" is not to cure people who have that illness because the return on investment isn't high enough...in fact, she can't receive treatment at all for it outside of primary care. This happens quite frequently with cancer/epilepsy outside the US too...the medicine exists, you just can't get it...
...and you are complaining about only having a "small selection of plans"...must be nice. Try selecting from one plan that might not cover you when you get sick (and if you get very sick, there might be nothing beyond primary care i.e. your local doctor who isn't a specialist).