Of course. But even in Vietnam's case, geography is clearly playing a major role. Policy differences can explain variation within SE Asia, but all of those countries have spikes at the same time, and are in a relative bubble of land travel in the continent (major border with China, which is more or less COVID-free due to authoritarian measures, lowly trafficked mountain ranges and undeveloped regions, and a thin strip connecting to Malaysia).

Seems like the main factors for success are: 1. Geography 2. Density 3. Freedom (or lack thereof) 4. Masks 5. Money