There is absolutely no question that SK's strict prevention measures are the cause of that. They were very strict from day one, no doubt because they were hit hard by SARS-CoV-1.
I lived in South Korea 2019-2021. On top of what you said above, they have a very good very intense contact tracing system, in SK the phone/bank/government are pretty inter-connected, it's not difficult for the government to literally hunt down cluster infections and force people into quarantine, and they did. They sent out over sms the exact times and locations of places people who had covid visited, etc, etc. I think contact tracing, Koreans taking it very seriously, wearing masks correctly, actually social distancing kept things under control. Koreans a very good at following instructions when they decide to, and they do it diligently.
Bullshit. People obeyed the first lockdown when everything was chaotic but since then it's been pretty hit and miss. People in the metro with no masks/mask under the nose, flouting of curfews, etc. If i had to guesstimate, around 20-30% of people didn't respect the social distancing and related measures.
As an outsider looking at France's news about vaccination rates and hesitancy, it certainly doesn't look like your fellow citizens trust public health officials. Although, I've never really had the impression that French people trusted authority. Quite the opposite.
But regardless, South Korea acted way quicker than any western democracy to test and trace.
The infection rate is also commensurate with general immune system fitness.
Remember in bad covid what we observe is vascular system failure, and we know that chronic hyperglycemia damages blood vessels. Combine that with non functional immune systems and this is what you get.
Switzerland has a higher life expectancy than South Korea, and has a very wealthy and healthy population.
Spain and Italy have both held the titles of "healthiest country in the world" in recent years.
All three have incidence rates more than an order of magnitude larger than South Korea.
Wearing respiratory protection equipment protects against respiratory contaminants. Testing people and tracing contacts helps to contain outbreaks. The answer is really that simple. South Korea was one of (if not) the first countries to start an aggressive testing and tracing program.
On TV, I watched their citizens line up in cars at mass testing sites months before my multi-billion-dollar healthcare conglomerate here in the US even had testing available at all.
That was only the first time, and only after the virus was everywhere. SK reacted much more rapidly when it initially came to them.
Furthermore, Schengen. SK are for all intents and purposes an island, and everything and everyone must come by either boat or plane, which helps with control.
It depends on the disease, covid is immensely correlated with diabetes / metabolic syndrome, which is rampant in many western countries with America at the top.