The actual data seems to indicate the exact opposite. Countries with large populations aren't able to provide inexpensive healthcare, while countries with smaller populations achieve better outcomes at a lower cost
edit: I've read some of your other comments on this post and I really enjoy the deep level of understanding you're bringing on the actual article's topic. I just think you're wrong about the specific scale thing that I'm talking about
We have a single payer system for everyone 65+, because we had the political will to do it, and it remains funded and functional because it is an important and powerful political bloc. A lot of people make a lot of money from the dysfunction of the system for everyone else and they fight tooth and nail to keep that gravy train flowing.