Will people still get infected? Yes, I'm sure they will since typical face masks are not P100. But when you're preventing ~80% transfer on an exhale and ~60% on inhale, if both participants had masks on then that filters a lot.
Granted this assumes other precautions would be followed as well since obviously places like bars and restaurants where you have no mask on will continue to be an issue.
For all intents and purposes, they don't have COVID.
Japan is seeing all-time record case counts:
https://www3.nhk.or.jp/nhkworld/en/news/tags/82/
South Korea is seeing infections growing "at their fastest pace since the early days of the pandemic":
https://www.reuters.com/article/uk-health-coronavirus-southk...
Taiwan is actually seeing case growth, as well (albeit from a small base):
https://www.worldometers.info/coronavirus/country/taiwan/
And not that you brought it up, but Hong Kong just saw an infection spike that has them instituting a bunch of new restrictions:
https://www.scmp.com/news/hong-kong/health-environment/artic...
How do you know that?