...each of these characters have retired from active duty in the Justice League.

Superman = retired from active duty with the jla just recently before the relaunch
Wonder Woman = retired from active duty during JLE
Aquaman = retired from active duty to be with mera
EM= retired from active duty to resurrect his wife
Kilowog = retired from active duty to train GLs
Martian Manhunter = retired from active duty after Breakdowns
Tomorrow Woman = retired herself from active duty by sacrificing herself.
Power Girl = retired from active duty with the JLE
Zatanna = retired from active JLA duty just recently

- l.k.