According to this recent article, the insurance broker Lockton Singapore has launched an insurance product to cover the cost of medical complications for medical travellers receiving surgery abroad.
The underwriter is QBE, the Australian general and reinsurance provider.
The article notes that residents from most countries around the world travelling to accredited hospitals are eligible for the policy. The policy only covers treatment in just over 300 hospitals accredited by JCI. JCI is an international accreditation body.
Eligibility includes most countries - but not the US. None of the 300 accredited hospitals are in the USA.
I suspect the reason is the high cost of medical care in the US - and the underwriter is not willing to bear that cost. This strategy will keep down the premiums for this coverage. It also excludes Americans from the benefits of the coverage at other world facilities.