For who? The insurer in Wyoming has no network of providers in New York with whom they have negotiated rates. Without that network they are at the mercy of whatever the New York provider charges. Because of that, every claim that the New York customer files will be out-of-network and will thus require a higher co-pay, a higher deductible and a lower percentage covered. It's lose/lose for both sides so why would the Wyoming company sell to the New York customer and why would the New York customer want to buy from the Wyoming insurer?
For the patient, if the out-of-state insurer can figure out how to lower the patient’s costs and still make a profit.
One law to consider would be to require service providers publish a cash/list price. Not sure how to compel that Constitutionally, but does seem a systemic problem is that providers don’t actually know _what_ their price is without having created an impenetrable list of negotiated costs.
Just because we can’t immediately see how it would work doesn’t mean that someone with connections & motive won’t make it work. Heck, one solution could be: insurer contacts provider and says “we’ll pay fair price $X for this, and if you don’t agree (or negotiate with us in good faith) you’ll have to get thru our enthusiastic lawyers to get anything out of our client who, by the way, doesn’t have anywhere close to $X.”