Each Green Lantern and Flash is representive of an era.
Silver Age: 60s/70s GL:
Alan Scott Flash:
Jay Garrick
Golden Age : 80s GL:
Hal Jordan Flash:
Barry Allen
Modern Age: 90s GL:
Kyle Rayner Flash:
Wally West
Millenum: 2000s GL:
John Stewart Flash:
Bart Allen
John Stewart is way more popular than Hal Jordan amongst anyone under 30... maybe under 40...
DC is completely aware of this, its why they are using the Wally West name on the Flash tv series. Anyone under 30 wants Wally West, not Barry Allen.
But they would rather go with a clearly dated character (Hal Jordan) than fund a project for an african american character that is several times more popular today (John Stewart)
That racism is so strong its hitting their pockets.
Cause I got no intention of paying for Superman v Batman or Justice League or any of their little cac films.
Can't wait for that Luke Cage and Black Panther tho...