These are not experts, they are deep state propagandists.
I mean, fortunately (or unfortunately), such processes have been going on for decades, and these experts have been in business for decades. So, nothing prevents us from analyzing their early models, explanations, projections, and forecasts, and comparing them with reality in order to form an opinion about the level of their expertise
> Their birth rate is already a massive problem.
Not exactly. Low birth rate itself is not a problem. What is a problem is the future consequences of low birth rate . And these consequences generally have not yet occurred, i.e. there is no problem yet.
> Koreans seem unwilling to consider more drastic measures
Yes, because there is no problem yet
> once it reaches the tipping point
Then it will become a problem and nothing will stop them from bringing in some foreign labor to fix it.
> They would need massive immigration to live there
Not that massive. Your ideas about the required amount of immigration to fix the labor shortage problem are probably formed by extrapolating Western immigration processes. But the point is that you can’t extrapolate like that. There are no obstacles to carrying out immigration tens of times more effectively than the West does.
Just to understand how irrelevant this issue is for Korea at the moment: the twentieth century was quite a turbulent time for Koreans, and now quite a lot of ethnic Koreans live outside of Korea. Many of them know the Korean language, want to move to Korea, but even with repatriation programs, this is not such an easy process. Korea has so many Koreans inside the country that they are quite reluctant to grant residence permits even to other Koreans with foreign citizenships.