Personally, the age when earning an annual salary of 100 million won is truly difficult

I think it's in your 50s
Among those in their 50s still steadily working at a company,
there are some who earn 100 million won,
but it seems like there are more people who have already retired
In your 60s, salaried employees themselves are rare,
and for most, an annual salary of 100 million won is just something they hit for a few years at their peak in their 40s..