I'd expect DuPont, BASF, Apple, Google, Intel, IBM, GE, Kodak if any of their labs remain, any number of biotech labs like Genentech might have that are sufficiently mat-sci adjacent, all of the major of universities; MIT, Harvard, etc. Any of the national labs. Sandia, Lawrence Livermore, whichever are appropriate. It's just that whole DEA and red phosphorus being a meth precursor making it difficult. Yay, war on drugs.
US does fine; likely in less of a rush to be first-past-the-post on announcing results. When the big US labs announce, they will likely be more careful and vetted and authoritative.
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.
