That's an oxymoron since nothing is actually free and from what we hear about UK healthcare, you get what you pay for. To answer the question regarding people who are not covered. Anyone who shows up in an emergency room at a hospital gets treatment and probably never pays. You will get different treatment if you are not insured though. I had an accident and fell and injured my face. The first question as I'm being wheeled into the emergency room was "do you have insurance?". I did so they called a plastic surgeon to fix my face. Otherwise, the resident on duty would have sewed me up. The treatment bill for this little accident came to $35,000 including $5,000 each for two CT Scans (one for my neck and the other for my head). Plus another thousand each for a doctor to read them. $1500 for the ambulance. $8,000 for the plastic surgeon and the rest for miscellaneous and the emergency room itself. So, if I didn't have insurance, I would have been billed $35,000 and if I couldn't pay it all or any of it, the hospital would have written it off as a loss. At the time, I had medicaid (which is the government insurance for poor people - I'll explain why if anyone wants that story) and medicaid has the lowest reimbursement rate of any insurer, even medicare (old folks insurance) so the total that medicaid paid was around $4500. It came out to be a little more than 10% of what was billed. I'm going into detail here because this explains how the hospitals convinced Congress that they were losing tons of money treating the uninsured for free. Even though they knew that if they treated an insured person, insurance companies would actually pay between 10 and 40% of what was billed, they always wrote off the uninsured treatment at the inflated price. Even though I never had to pay a cent, when I got the bill I was so incensed by the charges, especially the CT scans that I called the billing office at the hospital and complained that I didn't want to buy the #### machine, I wanted to rent it . This accident happened during the ObamaCare debate and made it clear (to me at least) that Congress was being lied to by lobbyists to inflate the cost of treating the uncovered. Earlier, I mentioned that posting prices would help with reducing costs. No one would ever go to Bridgeport hospital for a CT scan if their posted price were $5,000 when other facilities did the same procedure for around $500.
"Free" treatment for emergencies doesn't solve the problem of people who develop a chronic illness. There are charities that help but not as many as there used to be. In the past, there were lots of charity hospitals in the US. Most were run by religious orders and the Catholic hospitals were staffed by nuns. When I was 7, I had an operation in a Catholic hospital. My parents were poor but they still paid something because we weren't destitute, just poor. Most of those hospitals are gone now. Mostly due to the drop in church goers who supported the hospitals. The move away from religion is pushed mostly by liberals and at least in the case of the Catholic church due to scandals.
Congress can't fix the healthcare system because the problem is too big to solve in one chunk. It has to be broken down into pieces and no one will give up their pet component so nothing ever happens. It's like stopping illegal immigration. How can you give amnesty to the people already here before you shut down the borders? You can't so nothing gets done. The Republicans had both houses for Trump's two years. They had been railing about killing ObamaCare for 8 years. Did they do anything when they had the opportunity? NO!! A pox on all their houses. The Republicans are just as bad as the Democrats. They're just bad about different things. Both parties are great at making empty promises but Trump actually tries to implement what he promised. That's why his popularity is rising. If you didn't succumb to the perpetual wall of hate directed at him over the past three years by media and the Democrats, you could see he was like the energizer bunny. The man just keeps trying.
I'll end with, I don't think a very basic universal healthcare for all is a bad idea. But Congress has to stop selling it as FREE because only stupid people believe it is actually free. People have to be willing to pay for it and the cost has to correspondingly reduce the cost and coverage of the existing insurance options. It also cannot be administered by the government. We don't need one more bloated, inefficient bureaucracy that just spends "other people's" money with abandon.