> I see people praising leadership from places like New Zealand and South Korea, but maybe it is just easy to keep people out of these places.
There's two components to this. The first is indeed that both countries are relatively isolated islands. Yes, South Korea is technically a peninsula, but the part that connects it to the mainland is separated by the best guarded border in the world, so...
But the second component is how the situation was (and still is) handled: instead of waiting for exponential growth of the rate of new infections, both countries went into full emergency mode immediately. South Korea in particular applied lessons learned during the SARS crisis about a decade earlier and invested heavily in automated testing equipment, etc.
In Europe, one of the critical failures was the inability to quickly and cost-effectively ramp up testing due to the lack of automated lab equipment.
Other critical aspects of disease control included traceability, which worked exceptionally well in South Korea due to the excellent cell coverage and prevalence of smartphone app usage (plus permissive and practical data protection laws) and willing participation and support of the population.
New Zealand is quick to order measures even if a single case is being reported. This prevents exponential spreading and keeps measures such as lock-downs short and reduces the overall negative impact.
So it's really not just the location, but a number of measures that most other countries simply failed to take.
The geography helps a lot, though, no question.