Neither country took the middle ground compared to where the US was when we finally started reacting.

South Korea has been aggressively testing, contact chasing, and quarantining from day 1. Look at their number of tests per capita compared to ours.

China did indeed shut down the entire economy for months for provinces containing 900M people iirc. In barely hit provinces they have teams of thousands of people doing aggressive testing, contact tracing, and quarantine.

South Korea has tested 0.5% of their population by some accounts.

I mean, yes, that's great, but it's not as widespread as people are implying.

The number of new cases in South Korea has started to increase again, and they keep getting new clusters unlinked to any known cases: https://uk.reuters.com/article/uk-health-coronavirus-southko... I suspect that they're going to have to give up on the tracing and testing approach in the next few weeks.

Daily New Cases isn’t actually trending upward at this point;

https://www.worldometers.info/coronavirus/country/south-kore...

The article you linked is based on a single day’s new case count.