Originally Posted by
Vic Vega
DC allowed Vic Sage, Morpheus and Jack Knight story to end because they respected the writers involved and their wishes regarding to character.
Doomsday Clock like the Watchmen Prequel is pretty much a middle finger to Alan Moore since all the Watchmen characters got the Jack Knight treatment until relatively recently.
Jack Kirby was one of the hardest acts in the industry to follow and yet DC keeps trying with 4th World.
So even if DC made such a policy, they'd never adhere to it. Management can always change its mind and all bets
would be off.
The argument for stories to end is actually a ownership issue.
Since, if Denny O'Neil owned the classic Azreal he could have made sure that DC never brought him back if he didn't want it to happen.