So all these relatively lightly populated (to the US) isolated island nations from around the world like New Zealand, Fiji, Papua New Guinea, Seychelles, Gibraltar, New Caledonia & Iceland just by coincidence happen to have that key cultural determinant.
Whereas Vietnam, Singapore, South Korea and even Germany and the Scandinavian countries (with the notable exception of Sweden) - all doing way better than the US - don't count? The advantage countries of a smaller population may have is not geography or their borders but a homogeneity of approach. They may find it easier to achieve a consensus - because they may have a stronger sense of community and what is in their common good. As I said, the spread of the disease has been above all been a feature of how it has been responded to once it is in a country and not how it got there in the first place. In each country, the pandemic began with a handful of individuals.
If guided by science and good management, countries have achieved better outcomes. People will follow leaders they believe in and policies they think are right. The right approach has produced the best results. The same was open to the US and the UK but they dropped the ball. Above all, their leadership failed them. But the pandemic has also revealed the US in particular to be a country polarized and unable to agree on and apply a consistent approach to defeat the pandemic. That isnt "geography" but culture.