These are all countries with aggressive health programs developed in the aftermath of SARS and honed by H1N1. You're comparing apples and oranges not only in terms of border controls limiting ingress after recognition, but also SARS-CoV-2 first outbreak appears in the middle of a dense urban population. That initial outbreak was then allowed to gain a foothold as the government wrongfully silenced the people calling for help, vs. these three having aggressive policies to prevent suspect cases from entering the country on top of aggressive screening and testing policies spread across the urban lifescape.