For military exemption they need to set a bar which can't be cleared easily, and I think that caused the problem.
If the requirement was number of albums sold, or x number of weeks on Billboard, fandoms (probably also companies) would get to work focusing on meeting those goals, a lot of them could do it, and SK wouldn't want a flood of boy bands they've barely heard of getting out of doing their service.
I think BTS were told that if they won a Grammy that would become the exemption requirement for the KPop category, because it's a very hard thing to achieve. And I think Vegas was supposed to be a massive Grammy/exemption celebration.
So I think they're going to enlist, and it blows, because whether we're fans or not we can all see the huge amount of money and attention they've brought to Korea. But classical pianists must do more I guess...
. Musics of all over the world would like to win it