Sure, the government can say they'll only pay half as much as they do now, so providers will only provide half the care. Have you ever actually done any government procurement? Saying the government can just wave a magic wand and lower prices because "they said so" will only hurt the quality of care patients receive in the US.
The 'quality of care' you receive in the US is entirely dependent on your wealth and it's only the upper class that actually benefit from it.
You know what quality care I got as a poor person? Nothing, because my family couldn't afford it. I was given the privilege of going through highschool and college with teeth quite literally broken down to the gumlines and abscessed because it was either that or not being able to have a future.
I'm tired of hearing nonsense about quality of care because for a lot of people the quality is set to null.
Every time I read arguments online of people defending the American system, I almost always get hints that they are wealthy people, usually because they admit they can actually afford the care instead of essentially going broke over it. Healthcare debt is the leading cause of personal bankruptcy in the US, so it is statistically true that it is too much for the people below the median. Even for people in the middle class.
Genetics and diet seem to be large factors in dental health.
Poor people tend to not be able to afford healthy foods and will often eat foods high in sugars, which are terrible for your teeth. Perhaps their parents couldn't afford toothpaste regularly, or floss at all, or could only replace their toothbrushes once a year or two. Perhaps the parents work all the time, and don't have as much time or energy to instill strong daily tooth hygiene habits in their kids or police their brushing.
As an anecdotal data point, a friend of mine always goes for regular dental checkups, and brushes and flosses daily, but still has tartar buildup and gum issues. He had to get a deep-clean, and was in pain and bleeding for several days afterward. I (foolishly) avoided going to a dentist for many, many years, and in that time did a mediocre (at best) job of daily maintenance. When I finally started seeing a dentist again, I got away with two minor fillings (my first ones, and they didn't even numb me at all for the drilling) and a deep cleaning, where I had no bleeding issues and the pain was gone within a few hours (aside from tenderness around the anesthetic injection sites). My gums aren't in great shape, but are better off than my friend's. Unknown as to why the outcomes are so different. I can't imagine what my friend's teeth would be like if he didn't go to the dentist and didn't have good hygiene habits.
Thailand. Some of the best medical care of any developing nation, at around 10% of the price for most procedures. A night in a very clean, modern Thai hospital can be less than $100/night.