When you say cheaper do you mean (private) health insurance or directly paying for medical services, or both?
Thailand: paid out of pocket, no insurance. A trip to the ER for digestive issues took under an hour and the visit plus antibiotics cost under $200. This was at Bumrungrad, one of the best hospitals in Thailand.
I'll double-check, but I'm pretty confident my wife's care in the UK was under the NHS. Nepal was also her, I think it was out of pocket, but I'll check.
Nepal: she had some form of insurance. She doesn't know how much it cost, but presumably not much (she was volunteering for a non-profit) and her out-of-pocket costs were zero for a multi-day stay at a hospital.
UK: she doesn't remember having insurance, but thinks she must have (she was a student at the time). She used the NHS, again with no out-of-pocket expenses.
That's simply not true: per capita spending on healthcare (regardless of how that spending happens) is dramatically higher in the U.S. than anywhere else on the planet. For example, Germany spends 60% Per Capita compared to the U.S. https://www.pgpf.org/chart-archive/0006_health-care-oecd Spain spends just over 30% compared to the U.S.
And I've paid for/received healthcare in Portugal, Thailand, Nepal, and England. It's more cost effective (I started to say cheaper and better, but "better" is a loaded word) pretty much everywhere else.