BTS Military Plan Update, Will BTS Survive with ONLY 3 Members?

South Korea recently changed their legislation for military service concerning Kpop Idols.
With Jin's imminent mandatory military service looming in the distance getting closer and closer each day, could his departure from the group leave void that is impossible to fill? How will BTS change in coming years as other group members depart as well. Do changes need to be made to the South Korean military regarding enlistment and exemptions?