This is a growing problem...
I came up the usual "self-improver" way. I did a year flying out of Miami to some rather far-off islands using light twins without autopilots. You wouldn't want to fly into a busy terminal area doing that, so that a lot of the necessary skills for flying the line are not learned, but you certainly do master hand-flying and keeping your scan going.
Years later, I ended up flying a Dornier 328, having to learn modern systems I had only read about. (The 328 has Honeywell Primus 2000 glass, but no autothrottle.) There was a period of "What's it doing now?" but at least that was underpinned by the basic ability to revert to primary cues and fly the aircraft when the automation had been told to do something I did not want it to, such as taking us to the wrong waypoint. or ignoring the localizer because I had not armed APP.
The insidious thing is that hand-flying skills deteriorate if they are not used; I would take any good chance to practice, when the young FOs would groan when they heard that "cavalry charge" warning tone. Of course, later I could watch some of them really struggle in a sim session when one of the first systems to fail was the autopilot; they had obviously poor hand-flying skills. Some had probably never learned to do that very well, having been carried along through one of our infamous FAA-approved training mills, while others had simply not kept that skill up.
When it came to other things such as following a SID or a STAR then they were often superior to me; I was still essentially just a bush pilot in some ways, but which skill was primary? You need both skill sets, of course, but only one, being able to hand-fly without undue effort, is going to keep that thing dependably shiny side up!
A related problem, addressed on other threads, is the way that stall training has been perverted into an exercise in not losing any altitude. If you go in at 5 thousand feet, then you have to come out at that, even if that means sort of mushing along instead of making a very positive nose-down recovery from the stall. Well, usually not even a stall, of course, just the approach to a stall. It's easy to see how a real, full-breaking stall would come as a very nasty shock to someone only used to getting a bit of buffet or the stick shaker, and thinking that's the same as a stall flown to the break.
All of this seems like swaddling the flight crew in fluffy cotton, keeping them well away from the sharp edges implicit in flying any aircraft at the edge of its envelope, whether that's a critically low speed on final, or an upset in turbulence, or a stall, perhaps one encountered in icing at a speed taken to be above stall speed. I think that problem is spread across much of aviation now; I don't think it's specific to the culture of Korea. What happens as trouble approaches, whether good CRM is practiced, that might be culturally specific, but this lack of hand-flying skill is widespread, I think.