Who told you that they are not attempting the reproduction?
Even US labs are attempting it, some of them explicitly in the open like the Argonne National Laboratory.
Here you can find a non-comprehensive list of reproduction attempts: https://forums.spacebattles.com/threads/claims-of-room-tempe...
Oh, so there are finally Korean labs in that list! Last time there were 1 American, 1 Indian and 5 Chinese labs which I thought very weird. Hopefully the Korean labs can get an original sample.
This is probably about the fact that red phosphorus (required for the original process) cannot be purchased without a license (https://nitter.net/andrewmccalip/status/1684191067477004288#...), so kitchen chemists are out of the race. Established labs should have less problems though.