No, of course not and I didn't interpret what you've written that way.
“But nevertheless, to try to compare how these tiny country populations with the USA is not realistic”
- I can't see any reason why differences in population size would make different sorts of comparisons pointless.
You can always compare how successful two given countries are in different areas, even if one has a large population and the other has a pretty small one. You can look at how educational systems function, crime rates, economic growth etc, etc and make different conclusions about how well societies perform in these regards, try and finds reasons to the actual results and so on.
Population and ethnic mix are the key factors. That is why it is unrealistic to compare the tiny Scandinavian countries with the USA in general. A more valid comparison of things like health care, crime rates and education would be with small states with 90% people with the same race/culture , such as Maine or Vermont with Sweden.