***** NOT A TEACHER *****
Yes, it makes sense.
I think that most American teachers would recommend that a comma not be used after "days."
May I suggest a few little changes?
According to the South Korean government, most companies these days prefer group work in their offices. They believe that such
interaction among employees increases productivity and competitiveness.
P.S. If you start the sentence with "These days," then I think that you have a choice:
These days, most South Korean companies ....
These days most South Korean companies ....
I believe that most American newspapers, magazines, books, etc. would prefer the second sentence. They probably see
no real reason to use a comma. Most readers will just naturally pause after "days," so there is no need to use a comma in
order to "remind" them to pause. Because "these days" is only two words, there is no problem that readers will be confused.
(Did you notice that I used a comma after "words"? "Because 'these days' is only two words" is 7 words. That is a long
introduction. So we should help our readers by using a comma.)