I am shocked by that too. DD1 was born in NY 30 years ago, by CS - I believe the bill for surgery & staying in hospital for a week was c $2000, but anyway it was covered 100% by our insurance (which we'd had for 2 years. It was a HMI scheme though, which works kind of like the NHS, so more inclusive)
A friend of ours in his 60s had a severe stroke earlier this year & is currently in a rehab centre at a local hospital. The centre is a lovely place, quite new, lots of facilities, & all free of course.
DH recently wondered how a case like this would be managed in the US if you didn't have massive insurance; I mentioned this to DD1 & she told me about a friend of hers in NY whose father died when he was quite young, because he had cancer, & they couldn't afford the treatment, which is appalling in a supposedly civilised society

Our friend was resuscitated, repeatedly, by paramedics, then treated in hospital for weeks, then sent to one treatment centre for assessment, then on to the one where he is now. In the US, not being wealthy with massive insurance cover, he would probably just have died from the stroke.
I don't understand how the current Govt apparently can't see what a huge benefit to our society the NHS is 